nixcitizen/patches/wine_6.13_fastsync2.patch

diff --git a/configure b/configure
index 74c72003827..fe26bedfce6 100755
--- a/configure
+++ b/configure
@@ -7500,6 +7500,7 @@ for ac_header in \
 	linux/serial.h \
 	linux/types.h \
 	linux/ucdrom.h \
+	linux/winesync.h \
 	lwp.h \
 	mach-o/loader.h \
 	mach/mach.h \
diff --git a/configure.ac b/configure.ac
index dc43d73858f..9006299fee5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -480,6 +480,7 @@ AC_CHECK_HEADERS(\
 	linux/serial.h \
 	linux/types.h \
 	linux/ucdrom.h \
+	linux/winesync.h \
 	lwp.h \
 	mach-o/loader.h \
 	mach/mach.h \
diff --git a/dlls/kernel32/tests/sync.c b/dlls/kernel32/tests/sync.c
index 827f4c53aa0..36ed25b4db3 100644
--- a/dlls/kernel32/tests/sync.c
+++ b/dlls/kernel32/tests/sync.c
@@ -2778,6 +2778,84 @@ static void test_QueueUserAPC(void)
     ok(apc_count == 1, "APC count %u\n", apc_count);
 }
 
+static int zigzag_state, zigzag_count[2], zigzag_stop;
+
+static DWORD CALLBACK zigzag_event0(void *arg)
+{
+    HANDLE *events = arg;
+
+    while (!zigzag_stop)
+    {
+        WaitForSingleObject(events[0], INFINITE);
+        ResetEvent(events[0]);
+        ok(zigzag_state == 0, "got wrong state %d\n", zigzag_state);
+        zigzag_state++;
+        SetEvent(events[1]);
+        zigzag_count[0]++;
+    }
+    trace("thread 0 got done\n");
+    return 0;
+}
+
+static DWORD CALLBACK zigzag_event1(void *arg)
+{
+    HANDLE *events = arg;
+
+    while (!zigzag_stop)
+    {
+        WaitForSingleObject(events[1], INFINITE);
+        ResetEvent(events[1]);
+        ok(zigzag_state == 1, "got wrong state %d\n", zigzag_state);
+        zigzag_state--;
+        SetEvent(events[0]);
+        zigzag_count[1]++;
+    }
+    trace("thread 1 got done\n");
+    return 0;
+}
+
+static void test_zigzag_event(void)
+{
+    /* The basic idea is to test SetEvent/Wait back and forth between two
+     * threads. Each thread clears their own event, sets some common data,
+     * signals the other's, then waits on their own. We make sure the common
+     * data is always in the right state. We also print performance data. */
+
+    HANDLE threads[2], events[2];
+    BOOL ret;
+
+    events[0] = CreateEventA(NULL, FALSE, FALSE, NULL);
+    events[1] = CreateEventA(NULL, FALSE, FALSE, NULL);
+
+    threads[0] = CreateThread(NULL, 0, zigzag_event0, events, 0, NULL);
+    threads[1] = CreateThread(NULL, 0, zigzag_event1, events, 0, NULL);
+
+    zigzag_state = 0;
+    zigzag_count[0] = zigzag_count[1] = 0;
+    zigzag_stop = 0;
+
+    trace("starting zigzag test (events)\n");
+    SetEvent(events[0]);
+    Sleep(2000);
+    zigzag_stop = 1;
+    ret = WaitForMultipleObjects(2, threads, FALSE, INFINITE);
+    trace("%d\n", ret);
+    ok(ret == 0 || ret == 1, "wait failed: %u\n", ret);
+
+    ok(zigzag_count[0] == zigzag_count[1] || zigzag_count[0] == zigzag_count[1] + 1,
+        "count did not match: %d != %d\n", zigzag_count[0], zigzag_count[1]);
+
+    /* signal the other thread to finish, if it didn't already
+     * (in theory they both would at the same time, but there's a slight race on teardown if we get
+     * thread 1 SetEvent -> thread 0 ResetEvent -> thread 0 Wait -> thread 1 exits */
+    zigzag_state = 1-ret;
+    SetEvent(events[1-ret]);
+    ret = WaitForSingleObject(threads[1-ret], 1000);
+    ok(!ret, "wait failed: %u\n", ret);
+
+    trace("count: %d\n", zigzag_count[0]);
+}
+
 START_TEST(sync)
 {
     char **argv;
@@ -2843,5 +2921,6 @@ START_TEST(sync)
     test_srwlock_example();
     test_alertable_wait();
     test_apc_deadlock();
+    test_zigzag_event();
     test_crit_section();
 }
diff --git a/dlls/ntdll/unix/file.c b/dlls/ntdll/unix/file.c
index 21f5d10f3f8..a7b1ff15376 100644
--- a/dlls/ntdll/unix/file.c
+++ b/dlls/ntdll/unix/file.c
@@ -4690,7 +4690,7 @@ static async_data_t server_async( HANDLE handle, struct async_fileio *user, HAND
 
 static NTSTATUS wait_async( HANDLE handle, BOOL alertable )
 {
-    return NtWaitForSingleObject( handle, alertable, NULL );
+    return server_wait_for_object( handle, alertable, NULL );
 }
 
 /* callback for irp async I/O completion */
@@ -6021,7 +6021,7 @@ NTSTATUS WINAPI NtLockFile( HANDLE file, HANDLE event, PIO_APC_ROUTINE apc, void
         }
         if (handle)
         {
-            NtWaitForSingleObject( handle, FALSE, NULL );
+            server_wait_for_object( handle, FALSE, NULL );
             NtClose( handle );
         }
         else  /* Unix lock conflict, sleep a bit and retry */
diff --git a/dlls/ntdll/unix/process.c b/dlls/ntdll/unix/process.c
index c1ff0289cf2..153350be927 100644
--- a/dlls/ntdll/unix/process.c
+++ b/dlls/ntdll/unix/process.c
@@ -794,7 +794,7 @@ NTSTATUS WINAPI NtCreateUserProcess( HANDLE *process_handle_ptr, HANDLE *thread_
 
     /* wait for the new process info to be ready */
 
-    NtWaitForSingleObject( process_info, FALSE, NULL );
+    server_wait_for_object( process_info, FALSE, NULL );
     SERVER_START_REQ( get_new_process_info )
     {
         req->info = wine_server_obj_handle( process_info );
diff --git a/dlls/ntdll/unix/server.c b/dlls/ntdll/unix/server.c
index cec2ef250a3..5754f272b21 100644
--- a/dlls/ntdll/unix/server.c
+++ b/dlls/ntdll/unix/server.c
@@ -114,7 +114,7 @@ timeout_t server_start_time = 0;  /* time of server startup */
 sigset_t server_block_set;  /* signals to block during server calls */
 static int fd_socket = -1;  /* socket to exchange file descriptors with the server */
 static pid_t server_pid;
-static pthread_mutex_t fd_cache_mutex = PTHREAD_MUTEX_INITIALIZER;
+pthread_mutex_t fd_cache_mutex = PTHREAD_MUTEX_INITIALIZER;
 
 /* atomically exchange a 64-bit value */
 static inline LONG64 interlocked_xchg64( LONG64 *dest, LONG64 val )
@@ -354,7 +354,7 @@ static int wait_select_reply( void *cookie )
 /***********************************************************************
  *              invoke_user_apc
  */
-static NTSTATUS invoke_user_apc( CONTEXT *context, const user_apc_t *apc, NTSTATUS status )
+NTSTATUS invoke_user_apc( CONTEXT *context, const user_apc_t *apc, NTSTATUS status )
 {
     return call_user_apc_dispatcher( context, apc->args[0], apc->args[1], apc->args[2],
                                      wine_server_get_ptr( apc->func ), status );
@@ -685,6 +685,21 @@ unsigned int server_wait( const select_op_t *select_op, data_size_t size, UINT f
 }
 
 
+/* helper function to perform a server-side wait on an internal handle without
+ * using the fast synchronization path */
+unsigned int server_wait_for_object( HANDLE handle, BOOL alertable, const LARGE_INTEGER *timeout )
+{
+    select_op_t select_op;
+    UINT flags = SELECT_INTERRUPTIBLE;
+
+    if (alertable) flags |= SELECT_ALERTABLE;
+
+    select_op.wait.op = SELECT_WAIT;
+    select_op.wait.handles[0] = wine_server_obj_handle( handle );
+    return server_wait( &select_op, offsetof( select_op_t, wait.handles[1] ), flags, timeout );
+}
+
+
 /***********************************************************************
  *              NtContinue  (NTDLL.@)
  */
@@ -749,7 +764,7 @@ unsigned int server_queue_process_apc( HANDLE process, const apc_call_t *call, a
         }
         else
         {
-            NtWaitForSingleObject( handle, FALSE, NULL );
+            server_wait_for_object( handle, FALSE, NULL );
 
             SERVER_START_REQ( get_apc_result )
             {
@@ -1684,12 +1699,17 @@ NTSTATUS WINAPI NtDuplicateObject( HANDLE source_process, HANDLE source, HANDLE
         return result.dup_handle.status;
     }
 
+    /* hold fd_cache_mutex to prevent the fd from being added again between the
+     * call to remove_fd_from_cache and close_handle */
     server_enter_uninterrupted_section( &fd_cache_mutex, &sigset );
 
     /* always remove the cached fd; if the server request fails we'll just
      * retrieve it again */
     if (options & DUPLICATE_CLOSE_SOURCE)
+    {
         fd = remove_fd_from_cache( source );
+        close_fast_sync_obj( source );
+    }
 
     SERVER_START_REQ( dup_handle )
     {
@@ -1723,12 +1743,16 @@ NTSTATUS WINAPI NtClose( HANDLE handle )
     NTSTATUS ret;
     int fd;
 
+    /* hold fd_cache_mutex to prevent the fd from being added again between the
+     * call to remove_fd_from_cache and close_handle */
     server_enter_uninterrupted_section( &fd_cache_mutex, &sigset );
 
     /* always remove the cached fd; if the server request fails we'll just
      * retrieve it again */
     fd = remove_fd_from_cache( handle );
 
+    close_fast_sync_obj( handle );
+
     SERVER_START_REQ( close_handle )
     {
         req->handle = wine_server_obj_handle( handle );
diff --git a/dlls/ntdll/unix/signal_arm.c b/dlls/ntdll/unix/signal_arm.c
index f07f97930f1..e226225cd1a 100644
--- a/dlls/ntdll/unix/signal_arm.c
+++ b/dlls/ntdll/unix/signal_arm.c
@@ -765,6 +765,8 @@ static void usr1_handler( int signal, siginfo_t *siginfo, void *sigcontext )
         save_context( &context, sigcontext );
         wait_suspend( &context );
         restore_context( &context, sigcontext );
+
+    // FIXME: fast alertable waits...
     }
 }
 
@@ -840,14 +842,15 @@ void signal_init_process(void)
     if (sigaction( SIGABRT, &sig_act, NULL ) == -1) goto error;
     sig_act.sa_sigaction = quit_handler;
     if (sigaction( SIGQUIT, &sig_act, NULL ) == -1) goto error;
-    sig_act.sa_sigaction = usr1_handler;
-    if (sigaction( SIGUSR1, &sig_act, NULL ) == -1) goto error;
     sig_act.sa_sigaction = trap_handler;
     if (sigaction( SIGTRAP, &sig_act, NULL ) == -1) goto error;
     sig_act.sa_sigaction = segv_handler;
     if (sigaction( SIGSEGV, &sig_act, NULL ) == -1) goto error;
     if (sigaction( SIGILL, &sig_act, NULL ) == -1) goto error;
     if (sigaction( SIGBUS, &sig_act, NULL ) == -1) goto error;
+    sig_act.sa_sigaction = usr1_handler;
+    sig_act.sa_flags &= ~SA_RESTART; /* needed for fast sync alertable waits */
+    if (sigaction( SIGUSR1, &sig_act, NULL ) == -1) goto error;
     return;
 
  error:
diff --git a/dlls/ntdll/unix/signal_arm64.c b/dlls/ntdll/unix/signal_arm64.c
index 079064eee4b..206678206dc 100644
--- a/dlls/ntdll/unix/signal_arm64.c
+++ b/dlls/ntdll/unix/signal_arm64.c
@@ -922,6 +922,8 @@ static void usr1_handler( int signal, siginfo_t *siginfo, void *sigcontext )
         save_context( &context, sigcontext );
         wait_suspend( &context );
         restore_context( &context, sigcontext );
+
+    // FIXME: fast alertable waits...
     }
 }
 
@@ -1015,8 +1017,6 @@ void signal_init_process(void)
     if (sigaction( SIGABRT, &sig_act, NULL ) == -1) goto error;
     sig_act.sa_sigaction = quit_handler;
     if (sigaction( SIGQUIT, &sig_act, NULL ) == -1) goto error;
-    sig_act.sa_sigaction = usr1_handler;
-    if (sigaction( SIGUSR1, &sig_act, NULL ) == -1) goto error;
     sig_act.sa_sigaction = usr2_handler;
     if (sigaction( SIGUSR2, &sig_act, NULL ) == -1) goto error;
     sig_act.sa_sigaction = trap_handler;
@@ -1027,6 +1027,9 @@ void signal_init_process(void)
     if (sigaction( SIGILL, &sig_act, NULL ) == -1) goto error;
     sig_act.sa_sigaction = bus_handler;
     if (sigaction( SIGBUS, &sig_act, NULL ) == -1) goto error;
+    sig_act.sa_sigaction = usr1_handler;
+    sig_act.sa_flags &= ~SA_RESTART; /* needed for fast sync alertable waits */
+    if (sigaction( SIGUSR1, &sig_act, NULL ) == -1) goto error;
     return;
 
  error:
diff --git a/dlls/ntdll/unix/signal_i386.c b/dlls/ntdll/unix/signal_i386.c
index b5afbcf0aac..0a3b8dc115d 100644
--- a/dlls/ntdll/unix/signal_i386.c
+++ b/dlls/ntdll/unix/signal_i386.c
@@ -2010,6 +2010,9 @@ static void usr1_handler( int signal, siginfo_t *siginfo, void *sigcontext )
         NtGetContextThread( GetCurrentThread(), &xcontext.c );
         wait_suspend( &xcontext.c );
         NtSetContextThread( GetCurrentThread(), &xcontext.c );
+
+        if (ntdll_get_thread_data()->in_fast_alert_wait)
+            siglongjmp( ntdll_get_thread_data()->fast_alert_buf, 1 );
     }
     else
     {
@@ -2336,14 +2339,15 @@ void signal_init_process(void)
     if (sigaction( SIGABRT, &sig_act, NULL ) == -1) goto error;
     sig_act.sa_sigaction = quit_handler;
     if (sigaction( SIGQUIT, &sig_act, NULL ) == -1) goto error;
-    sig_act.sa_sigaction = usr1_handler;
-    if (sigaction( SIGUSR1, &sig_act, NULL ) == -1) goto error;
     sig_act.sa_sigaction = trap_handler;
     if (sigaction( SIGTRAP, &sig_act, NULL ) == -1) goto error;
     sig_act.sa_sigaction = segv_handler;
     if (sigaction( SIGSEGV, &sig_act, NULL ) == -1) goto error;
     if (sigaction( SIGILL, &sig_act, NULL ) == -1) goto error;
     if (sigaction( SIGBUS, &sig_act, NULL ) == -1) goto error;
+    sig_act.sa_sigaction = usr1_handler;
+    sig_act.sa_flags &= ~SA_RESTART; /* needed for fast sync alertable waits */
+    if (sigaction( SIGUSR1, &sig_act, NULL ) == -1) goto error;
     return;
 
  error:
diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
index 148e3641d0e..4d6201e7156 100644
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -2478,6 +2478,9 @@ static void usr1_handler( int signal, siginfo_t *siginfo, void *ucontext )
         NtGetContextThread( GetCurrentThread(), &context.c );
         wait_suspend( &context.c );
         NtSetContextThread( GetCurrentThread(), &context.c );
+
+        if (ntdll_get_thread_data()->in_fast_alert_wait)
+            siglongjmp( ntdll_get_thread_data()->fast_alert_buf, 1 );
     }
     else
     {
@@ -2649,14 +2652,15 @@ void signal_init_process(void)
     if (sigaction( SIGABRT, &sig_act, NULL ) == -1) goto error;
     sig_act.sa_sigaction = quit_handler;
     if (sigaction( SIGQUIT, &sig_act, NULL ) == -1) goto error;
-    sig_act.sa_sigaction = usr1_handler;
-    if (sigaction( SIGUSR1, &sig_act, NULL ) == -1) goto error;
     sig_act.sa_sigaction = trap_handler;
     if (sigaction( SIGTRAP, &sig_act, NULL ) == -1) goto error;
     sig_act.sa_sigaction = segv_handler;
     if (sigaction( SIGSEGV, &sig_act, NULL ) == -1) goto error;
     if (sigaction( SIGILL, &sig_act, NULL ) == -1) goto error;
     if (sigaction( SIGBUS, &sig_act, NULL ) == -1) goto error;
+    sig_act.sa_sigaction = usr1_handler;
+    sig_act.sa_flags &= ~SA_RESTART; /* needed for fast sync alertable waits */
+    if (sigaction( SIGUSR1, &sig_act, NULL ) == -1) goto error;
     return;
 
  error:
diff --git a/dlls/ntdll/unix/socket.c b/dlls/ntdll/unix/socket.c
index c1cd319ccf9..2e9f5230629 100644
--- a/dlls/ntdll/unix/socket.c
+++ b/dlls/ntdll/unix/socket.c
@@ -107,7 +107,7 @@ static async_data_t server_async( HANDLE handle, struct async_fileio *user, HAND
 
 static NTSTATUS wait_async( HANDLE handle, BOOL alertable )
 {
-    return NtWaitForSingleObject( handle, alertable, NULL );
+    return server_wait_for_object( handle, alertable, NULL );
 }
 
 union unix_sockaddr
diff --git a/dlls/ntdll/unix/sync.c b/dlls/ntdll/unix/sync.c
index 16635ee42fa..31af5cf8040 100644
--- a/dlls/ntdll/unix/sync.c
+++ b/dlls/ntdll/unix/sync.c
@@ -30,8 +30,15 @@
 
 #include <assert.h>
 #include <errno.h>
+#include <inttypes.h>
 #include <limits.h>
 #include <signal.h>
+#ifdef HAVE_SYS_IOCTL_H
+#include <sys/ioctl.h>
+#endif
+#ifdef HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+#endif
 #ifdef HAVE_SYS_SYSCALL_H
 #include <sys/syscall.h>
 #endif
@@ -61,6 +68,9 @@
 # include <mach/semaphore.h>
 # include <mach/mach_time.h>
 #endif
+#ifdef HAVE_LINUX_WINESYNC_H
+# include <linux/winesync.h>
+#endif
 
 #include "ntstatus.h"
 #define WIN32_NO_STATUS
@@ -141,173 +151,1194 @@ static inline int use_futexes(void)
 {
     static int supported = -1;
 
-    if (supported == -1)
+    if (supported == -1)
+    {
+        futex_wait( &supported, 10, NULL );
+        if (errno == ENOSYS)
+        {
+            futex_private = 0;
+            futex_wait( &supported, 10, NULL );
+        }
+        supported = (errno != ENOSYS);
+    }
+    return supported;
+}
+
+static int *get_futex(void **ptr)
+{
+    if (sizeof(void *) == 8)
+        return (int *)((((ULONG_PTR)ptr) + 3) & ~3);
+    else if (!(((ULONG_PTR)ptr) & 3))
+        return (int *)ptr;
+    else
+        return NULL;
+}
+
+static void timespec_from_timeout( struct timespec *timespec, const LARGE_INTEGER *timeout )
+{
+    LARGE_INTEGER now;
+    timeout_t diff;
+
+    if (timeout->QuadPart > 0)
+    {
+        NtQuerySystemTime( &now );
+        diff = timeout->QuadPart - now.QuadPart;
+    }
+    else
+        diff = -timeout->QuadPart;
+
+    timespec->tv_sec  = diff / TICKSPERSEC;
+    timespec->tv_nsec = (diff % TICKSPERSEC) * 100;
+}
+
+#endif
+
+
+static BOOL compare_addr( const void *addr, const void *cmp, SIZE_T size )
+{
+    switch (size)
+    {
+        case 1:
+            return (*(const UCHAR *)addr == *(const UCHAR *)cmp);
+        case 2:
+            return (*(const USHORT *)addr == *(const USHORT *)cmp);
+        case 4:
+            return (*(const ULONG *)addr == *(const ULONG *)cmp);
+        case 8:
+            return (*(const ULONG64 *)addr == *(const ULONG64 *)cmp);
+    }
+
+    return FALSE;
+}
+
+
+static const char *debugstr_timeout( const LARGE_INTEGER *timeout )
+{
+    if (!timeout) return "<infinite>";
+    return wine_dbg_sprintf( "%ld.%07ld", (long)timeout->QuadPart / TICKSPERSEC,
+                             (long)timeout->QuadPart % TICKSPERSEC );
+}
+
+
+/* create a struct security_descriptor and contained information in one contiguous piece of memory */
+NTSTATUS alloc_object_attributes( const OBJECT_ATTRIBUTES *attr, struct object_attributes **ret,
+                                  data_size_t *ret_len )
+{
+    unsigned int len = sizeof(**ret);
+    SID *owner = NULL, *group = NULL;
+    ACL *dacl = NULL, *sacl = NULL;
+    SECURITY_DESCRIPTOR *sd;
+
+    *ret = NULL;
+    *ret_len = 0;
+
+    if (!attr) return STATUS_SUCCESS;
+
+    if (attr->Length != sizeof(*attr)) return STATUS_INVALID_PARAMETER;
+
+    if ((sd = attr->SecurityDescriptor))
+    {
+        len += sizeof(struct security_descriptor);
+	if (sd->Revision != SECURITY_DESCRIPTOR_REVISION) return STATUS_UNKNOWN_REVISION;
+        if (sd->Control & SE_SELF_RELATIVE)
+        {
+            SECURITY_DESCRIPTOR_RELATIVE *rel = (SECURITY_DESCRIPTOR_RELATIVE *)sd;
+            if (rel->Owner) owner = (PSID)((BYTE *)rel + rel->Owner);
+            if (rel->Group) group = (PSID)((BYTE *)rel + rel->Group);
+            if ((sd->Control & SE_SACL_PRESENT) && rel->Sacl) sacl = (PSID)((BYTE *)rel + rel->Sacl);
+            if ((sd->Control & SE_DACL_PRESENT) && rel->Dacl) dacl = (PSID)((BYTE *)rel + rel->Dacl);
+        }
+        else
+        {
+            owner = sd->Owner;
+            group = sd->Group;
+            if (sd->Control & SE_SACL_PRESENT) sacl = sd->Sacl;
+            if (sd->Control & SE_DACL_PRESENT) dacl = sd->Dacl;
+        }
+
+        if (owner) len += offsetof( SID, SubAuthority[owner->SubAuthorityCount] );
+        if (group) len += offsetof( SID, SubAuthority[group->SubAuthorityCount] );
+        if (sacl) len += sacl->AclSize;
+        if (dacl) len += dacl->AclSize;
+
+        /* fix alignment for the Unicode name that follows the structure */
+        len = (len + sizeof(WCHAR) - 1) & ~(sizeof(WCHAR) - 1);
+    }
+
+    if (attr->ObjectName)
+    {
+        if (attr->ObjectName->Length & (sizeof(WCHAR) - 1)) return STATUS_OBJECT_NAME_INVALID;
+        len += attr->ObjectName->Length;
+    }
+    else if (attr->RootDirectory) return STATUS_OBJECT_NAME_INVALID;
+
+    len = (len + 3) & ~3;  /* DWORD-align the entire structure */
+
+    if (!(*ret = calloc( len, 1 ))) return STATUS_NO_MEMORY;
+
+    (*ret)->rootdir = wine_server_obj_handle( attr->RootDirectory );
+    (*ret)->attributes = attr->Attributes;
+
+    if (attr->SecurityDescriptor)
+    {
+        struct security_descriptor *descr = (struct security_descriptor *)(*ret + 1);
+        unsigned char *ptr = (unsigned char *)(descr + 1);
+
+        descr->control = sd->Control & ~SE_SELF_RELATIVE;
+        if (owner) descr->owner_len = offsetof( SID, SubAuthority[owner->SubAuthorityCount] );
+        if (group) descr->group_len = offsetof( SID, SubAuthority[group->SubAuthorityCount] );
+        if (sacl) descr->sacl_len = sacl->AclSize;
+        if (dacl) descr->dacl_len = dacl->AclSize;
+
+        memcpy( ptr, owner, descr->owner_len );
+        ptr += descr->owner_len;
+        memcpy( ptr, group, descr->group_len );
+        ptr += descr->group_len;
+        memcpy( ptr, sacl, descr->sacl_len );
+        ptr += descr->sacl_len;
+        memcpy( ptr, dacl, descr->dacl_len );
+        (*ret)->sd_len = (sizeof(*descr) + descr->owner_len + descr->group_len + descr->sacl_len +
+                          descr->dacl_len + sizeof(WCHAR) - 1) & ~(sizeof(WCHAR) - 1);
+    }
+
+    if (attr->ObjectName)
+    {
+        unsigned char *ptr = (unsigned char *)(*ret + 1) + (*ret)->sd_len;
+        (*ret)->name_len = attr->ObjectName->Length;
+        memcpy( ptr, attr->ObjectName->Buffer, (*ret)->name_len );
+    }
+
+    *ret_len = len;
+    return STATUS_SUCCESS;
+}
+
+
+static NTSTATUS validate_open_object_attributes( const OBJECT_ATTRIBUTES *attr )
+{
+    if (!attr || attr->Length != sizeof(*attr)) return STATUS_INVALID_PARAMETER;
+
+    if (attr->ObjectName)
+    {
+        if (attr->ObjectName->Length & (sizeof(WCHAR) - 1)) return STATUS_OBJECT_NAME_INVALID;
+    }
+    else if (attr->RootDirectory) return STATUS_OBJECT_NAME_INVALID;
+
+    return STATUS_SUCCESS;
+}
+
+
+#ifdef HAVE_LINUX_WINESYNC_H
+
+static int get_fast_sync_device(void)
+{
+    static int fast_sync_fd = -2;
+
+    if (fast_sync_fd == -2)
+    {
+        HANDLE device;
+        int fd, needs_close;
+        NTSTATUS ret;
+
+        SERVER_START_REQ( get_fast_sync_device )
+        {
+            if (!(ret = wine_server_call( req ))) device = wine_server_ptr_handle( reply->handle );
+        }
+        SERVER_END_REQ;
+
+        if (!ret)
+        {
+            if (!server_get_unix_fd( device, 0, &fd, &needs_close, NULL, NULL ))
+            {
+                if (InterlockedCompareExchange( &fast_sync_fd, fd, -2 ) != -2)
+                {
+                    /* someone beat us to it */
+                    if (needs_close) close( fd );
+                    NtClose( device );
+                }
+                /* otherwise don't close the device */
+            }
+            else
+            {
+                InterlockedCompareExchange( &fast_sync_fd, -1, -2 );
+                NtClose( device );
+            }
+        }
+        else
+        {
+            InterlockedCompareExchange( &fast_sync_fd, -1, -2 );
+        }
+    }
+    return fast_sync_fd;
+}
+
+/* It's possible for synchronization primitives to remain alive even after being
+ * closed, because a thread is still waiting on them. It's rare in practice, and
+ * documented as being undefined behaviour by Microsoft, but it works, and some
+ * applications rely on it. This means we need to refcount handles, and defer
+ * deleting them on the server side until the refcount reaches zero. We do this
+ * by having each client process hold a handle to the fast synchronization
+ * object, as well as a private refcount. When the client refcount reaches zero,
+ * it closes the handle; when all handles are closed, the server deletes the
+ * fast synchronization object.
+ *
+ * We also need this for signal-and-wait. The signal and wait operations aren't
+ * atomic, but we can't perform the signal and then return STATUS_INVALID_HANDLE
+ * for the wait—we need to either do both operations or neither. That means we
+ * need to grab references to both objects, and prevent them from being
+ * destroyed before we're done with them.
+ *
+ * We want lookup of objects from the cache to be very fast; ideally, it should
+ * be lock-free. We achieve this by using atomic modifications to "refcount",
+ * and guaranteeing that all other fields are valid and correct *as long as*
+ * refcount is nonzero, and we store the entire structure in memory which will
+ * never be freed.
+ *
+ * This means that acquiring the object can't use a simple atomic increment; it
+ * has to use a compare-and-swap loop to ensure that it doesn't try to increment
+ * an object with a zero refcount. That's still leagues better than a real lock,
+ * though, and release can be a single atomic decrement.
+ *
+ * It also means that threads modifying the cache need to take a lock, to
+ * prevent other threads from writing to it concurrently.
+ *
+ * It's possible for an object currently in use (by a waiter) to be closed and
+ * the same handle immediately reallocated to a different object. This should be
+ * a very rare situation, and in that case we simply don't cache the handle.
+ */
+struct fast_sync_cache_entry
+{
+    LONG refcount;
+    unsigned int obj;
+    enum fast_sync_type type;
+    unsigned int access;
+    BOOL closed;
+    /* handle to the underlying fast sync object, stored as obj_handle_t to save
+     * space */
+    obj_handle_t handle;
+};
+
+
+static void release_fast_sync_obj( struct fast_sync_cache_entry *cache )
+{
+    /* save the handle now; as soon as the refcount hits 0 we cannot access the
+     * cache anymore */
+    HANDLE handle = wine_server_ptr_handle( cache->handle );
+    LONG refcount = InterlockedDecrement( &cache->refcount );
+
+    assert( refcount >= 0 );
+
+    if (!refcount)
+    {
+        NTSTATUS ret;
+
+        /* we can't call NtClose here as we may be inside fd_cache_mutex */
+        SERVER_START_REQ( close_handle )
+        {
+            req->handle = wine_server_obj_handle( handle );
+            ret = wine_server_call( req );
+        }
+        SERVER_END_REQ;
+
+        assert( !ret );
+    }
+}
+
+
+#define FAST_SYNC_CACHE_BLOCK_SIZE  (65536 / sizeof(struct fast_sync_cache_entry))
+#define FAST_SYNC_CACHE_ENTRIES     128
+
+static struct fast_sync_cache_entry *fast_sync_cache[FAST_SYNC_CACHE_ENTRIES];
+static struct fast_sync_cache_entry fast_sync_cache_initial_block[FAST_SYNC_CACHE_BLOCK_SIZE];
+
+static inline unsigned int handle_to_index( HANDLE handle, unsigned int *entry )
+{
+    unsigned int idx = (wine_server_obj_handle(handle) >> 2) - 1;
+    *entry = idx / FAST_SYNC_CACHE_BLOCK_SIZE;
+    return idx % FAST_SYNC_CACHE_BLOCK_SIZE;
+}
+
+
+static struct fast_sync_cache_entry *cache_fast_sync_obj( HANDLE handle, obj_handle_t fast_sync, int obj,
+                                                          enum fast_sync_type type, unsigned int access )
+{
+    unsigned int entry, idx = handle_to_index( handle, &entry );
+    struct fast_sync_cache_entry *cache;
+    sigset_t sigset;
+    int refcount;
+
+    if (entry >= FAST_SYNC_CACHE_ENTRIES)
+    {
+        FIXME( "too many allocated handles, not caching %p\n", handle );
+        return NULL;
+    }
+
+    if (!fast_sync_cache[entry])  /* do we need to allocate a new block of entries? */
+    {
+        if (!entry) fast_sync_cache[0] = fast_sync_cache_initial_block;
+        else
+        {
+            static const size_t size = FAST_SYNC_CACHE_BLOCK_SIZE * sizeof(struct fast_sync_cache_entry);
+            void *ptr = anon_mmap_alloc( size, PROT_READ | PROT_WRITE );
+            if (ptr == MAP_FAILED) return NULL;
+            if (InterlockedCompareExchangePointer( (void **)&fast_sync_cache[entry], ptr, NULL ))
+                munmap( ptr, size ); /* someone beat us to it */
+        }
+    }
+
+    cache = &fast_sync_cache[entry][idx];
+
+    /* Hold fd_cache_mutex instead of a separate mutex, to prevent the same
+     * race between this function and NtClose. That is, prevent the object from
+     * being cached again between close_fast_sync_obj() and close_handle. */
+    server_enter_uninterrupted_section( &fd_cache_mutex, &sigset );
+
+    if (InterlockedCompareExchange( &cache->refcount, 0, 0 ))
+    {
+        /* We lost the race with another thread trying to cache this object, or
+         * the handle is currently being used for another object (i.e. it was
+         * closed and then reused). We have no way of knowing which, and in the
+         * latter case we can't cache this object until the old one is
+         * completely destroyed, so always return failure. */
+        server_leave_uninterrupted_section( &fd_cache_mutex, &sigset );
+        return NULL;
+    }
+
+    cache->handle = fast_sync;
+    cache->obj = obj;
+    cache->type = type;
+    cache->access = access;
+    cache->closed = FALSE;
+    /* make sure we set the other members before the refcount; this store needs
+     * release semantics [paired with the load in get_cached_fast_sync_obj()]
+     * set the refcount to 2 (one for the handle, one for the caller) */
+    refcount = InterlockedExchange( &cache->refcount, 2 );
+    assert( !refcount );
+
+    server_leave_uninterrupted_section( &fd_cache_mutex, &sigset );
+
+    return cache;
+}
+
+
+/* returns the previous value */
+static inline LONG interlocked_inc_if_nonzero( LONG *dest )
+{
+    LONG val, tmp;
+    for (val = *dest;; val = tmp)
+    {
+        if (!val || (tmp = InterlockedCompareExchange( dest, val + 1, val )) == val)
+            break;
+    }
+    return val;
+}
+
+
+static struct fast_sync_cache_entry *get_cached_fast_sync_obj( HANDLE handle )
+{
+    unsigned int entry, idx = handle_to_index( handle, &entry );
+    struct fast_sync_cache_entry *cache;
+
+    if (entry >= FAST_SYNC_CACHE_ENTRIES || !fast_sync_cache[entry])
+        return NULL;
+
+    cache = &fast_sync_cache[entry][idx];
+
+    /* this load needs acquire semantics [paired with the store in
+     * cache_fast_sync_obj()] */
+    if (!interlocked_inc_if_nonzero( &cache->refcount ))
+        return NULL;
+
+    if (cache->closed)
+    {
+        /* The object is still being used, but "handle" has been closed. The
+         * handle value might have been reused for another object in the
+         * meantime, in which case we have to report that valid object, so
+         * force the caller to check the server. */
+        release_fast_sync_obj( cache );
+        return NULL;
+    }
+
+    return cache;
+}
+
+
+/* returns a pointer to a cache entry; if the object could not be cached,
+ * returns "stack_cache" instead, which should be allocated on stack */
+static NTSTATUS get_fast_sync_obj( HANDLE handle, enum fast_sync_type desired_type, ACCESS_MASK desired_access,
+                                   struct fast_sync_cache_entry *stack_cache,
+                                   struct fast_sync_cache_entry **ret_cache )
+{
+    struct fast_sync_cache_entry *cache;
+    obj_handle_t fast_sync_handle;
+    enum fast_sync_type type;
+    unsigned int access;
+    NTSTATUS ret;
+    int obj;
+
+    /* try to find it in the cache already */
+    if ((cache = get_cached_fast_sync_obj( handle )))
+    {
+        *ret_cache = cache;
+        return STATUS_SUCCESS;
+    }
+
+    /* try to retrieve it from the server */
+    SERVER_START_REQ( get_fast_sync_obj )
+    {
+        req->handle = wine_server_obj_handle( handle );
+        if (!(ret = wine_server_call( req )))
+        {
+            fast_sync_handle = reply->handle;
+            access = reply->access;
+            type = reply->type;
+            obj = reply->obj;
+        }
+    }
+    SERVER_END_REQ;
+
+    if (ret) return ret;
+
+    cache = cache_fast_sync_obj( handle, fast_sync_handle, obj, type, access );
+    if (!cache)
+    {
+        cache = stack_cache;
+        cache->handle = fast_sync_handle;
+        cache->obj = obj;
+        cache->type = type;
+        cache->access = access;
+        cache->closed = FALSE;
+        cache->refcount = 1;
+    }
+
+    *ret_cache = cache;
+
+    if (desired_type && desired_type != cache->type)
+    {
+        release_fast_sync_obj( cache );
+        return STATUS_OBJECT_TYPE_MISMATCH;
+    }
+
+    if ((cache->access & desired_access) != desired_access)
+    {
+        release_fast_sync_obj( cache );
+        return STATUS_ACCESS_DENIED;
+    }
+
+    return STATUS_SUCCESS;
+}
+
+
+/* caller must hold fd_cache_mutex */
+void close_fast_sync_obj( HANDLE handle )
+{
+    struct fast_sync_cache_entry *cache = get_cached_fast_sync_obj( handle );
+
+    if (cache)
+    {
+        cache->closed = TRUE;
+        /* once for the reference we just grabbed, and once for the handle */
+        release_fast_sync_obj( cache );
+        release_fast_sync_obj( cache );
+    }
+}
+
+
+static NTSTATUS fast_release_semaphore_obj( int device, unsigned int obj, ULONG count, ULONG *prev_count )
+{
+    struct winesync_sem_args args = {0};
+    NTSTATUS ret;
+
+    args.sem = obj;
+    args.count = count;
+    ret = ioctl( device, WINESYNC_IOC_PUT_SEM, &args );
+    if (ret < 0)
+    {
+        if (errno == EOVERFLOW)
+            return STATUS_SEMAPHORE_LIMIT_EXCEEDED;
+        else
+            return errno_to_status( errno );
+    }
+    if (prev_count) *prev_count = args.count;
+    return STATUS_SUCCESS;
+}
+
+
+static NTSTATUS fast_release_semaphore( HANDLE handle, ULONG count, ULONG *prev_count )
+{
+    struct fast_sync_cache_entry stack_cache, *cache;
+    NTSTATUS ret;
+    int device;
+
+    if ((device = get_fast_sync_device()) < 0)
+        return STATUS_NOT_IMPLEMENTED;
+
+    if ((ret = get_fast_sync_obj( handle, FAST_SYNC_SEMAPHORE,
+                                  SEMAPHORE_MODIFY_STATE, &stack_cache, &cache )))
+        return ret;
+
+    ret = fast_release_semaphore_obj( device, cache->obj, count, prev_count );
+
+    release_fast_sync_obj( cache );
+    return ret;
+}
+
+
+static NTSTATUS fast_query_semaphore_obj( int device, unsigned int obj, SEMAPHORE_BASIC_INFORMATION *info )
+{
+    struct winesync_sem_args args = {0};
+    NTSTATUS ret;
+
+    args.sem = obj;
+    ret = ioctl( device, WINESYNC_IOC_READ_SEM, &args );
+
+    if (ret < 0)
+        return errno_to_status( errno );
+    info->CurrentCount = args.count;
+    info->MaximumCount = args.max;
+    return STATUS_SUCCESS;
+}
+
+
+static NTSTATUS fast_query_semaphore( HANDLE handle, SEMAPHORE_BASIC_INFORMATION *info )
+{
+    struct fast_sync_cache_entry stack_cache, *cache;
+    NTSTATUS ret;
+    int device;
+
+    if ((device = get_fast_sync_device()) < 0)
+        return STATUS_NOT_IMPLEMENTED;
+
+    if ((ret = get_fast_sync_obj( handle, FAST_SYNC_SEMAPHORE,
+                                  SEMAPHORE_QUERY_STATE, &stack_cache, &cache )))
+        return ret;
+
+    ret = fast_query_semaphore_obj( device, cache->obj, info );
+
+    release_fast_sync_obj( cache );
+    return ret;
+}
+
+
+static NTSTATUS fast_set_event_obj( int device, unsigned int obj, LONG *prev_state )
+{
+    struct winesync_sem_args args = {0};
+    NTSTATUS ret;
+
+    args.sem = obj;
+    args.count = 1;
+    ret = ioctl( device, WINESYNC_IOC_PUT_SEM, &args );
+    if (ret < 0)
+    {
+        if (errno == EOVERFLOW)
+        {
+            if (prev_state) *prev_state = 1;
+            return STATUS_SUCCESS;
+        }
+        else
+            return errno_to_status( errno );
+    }
+    if (prev_state) *prev_state = 0;
+    return STATUS_SUCCESS;
+}
+
+
+static NTSTATUS fast_set_event( HANDLE handle, LONG *prev_state )
+{
+    struct fast_sync_cache_entry stack_cache, *cache;
+    NTSTATUS ret;
+    int device;
+
+    if ((device = get_fast_sync_device()) < 0)
+        return STATUS_NOT_IMPLEMENTED;
+
+    if ((ret = get_fast_sync_obj( handle, FAST_SYNC_EVENT, EVENT_MODIFY_STATE,
+                                  &stack_cache, &cache )))
+        return ret;
+
+    ret = fast_set_event_obj( device, cache->obj, prev_state );
+
+    release_fast_sync_obj( cache );
+    return ret;
+}
+
+
+static NTSTATUS fast_reset_event_obj( int device, unsigned int obj, LONG *prev_state )
+{
+    NTSTATUS ret;
+
+    ret = ioctl( device, WINESYNC_IOC_GET_SEM, &obj );
+    if (ret < 0)
+    {
+        if (errno == EWOULDBLOCK)
+        {
+            if (prev_state) *prev_state = 0;
+            return STATUS_SUCCESS;
+        }
+        else
+            return errno_to_status( errno );
+    }
+    if (prev_state) *prev_state = 1;
+    return STATUS_SUCCESS;
+}
+
+
+static NTSTATUS fast_reset_event( HANDLE handle, LONG *prev_state )
+{
+    struct fast_sync_cache_entry stack_cache, *cache;
+    NTSTATUS ret;
+    int device;
+
+    if ((device = get_fast_sync_device()) < 0)
+        return STATUS_NOT_IMPLEMENTED;
+
+    if ((ret = get_fast_sync_obj( handle, FAST_SYNC_EVENT, EVENT_MODIFY_STATE,
+                                  &stack_cache, &cache )))
+        return ret;
+
+    ret = fast_reset_event_obj( device, cache->obj, prev_state );
+
+    release_fast_sync_obj( cache );
+    return ret;
+}
+
+
+static NTSTATUS fast_pulse_event_obj( int device, unsigned int obj, LONG *prev_state )
+{
+    struct winesync_sem_args args = {0};
+    NTSTATUS ret;
+
+    args.sem = obj;
+    args.count = 1;
+    ret = ioctl( device, WINESYNC_IOC_PULSE_SEM, &args );
+    if (ret < 0)
+    {
+        if (errno == EOVERFLOW)
+        {
+            if (prev_state) *prev_state = 1;
+            return STATUS_SUCCESS;
+        }
+        else
+            return errno_to_status( errno );
+    }
+    if (prev_state) *prev_state = 0;
+    return STATUS_SUCCESS;
+}
+
+
+static NTSTATUS fast_pulse_event( HANDLE handle, LONG *prev_state )
+{
+    struct fast_sync_cache_entry stack_cache, *cache;
+    NTSTATUS ret;
+    int device;
+
+    if ((device = get_fast_sync_device()) < 0)
+        return STATUS_NOT_IMPLEMENTED;
+
+    if ((ret = get_fast_sync_obj( handle, FAST_SYNC_EVENT, EVENT_MODIFY_STATE,
+                                  &stack_cache, &cache )))
+        return ret;
+
+    ret = fast_pulse_event_obj( device, cache->obj, prev_state );
+
+    release_fast_sync_obj( cache );
+    return ret;
+}
+
+
+static NTSTATUS fast_query_event_obj( int device, unsigned int obj, EVENT_BASIC_INFORMATION *info )
+{
+    struct winesync_sem_args args = {0};
+    NTSTATUS ret;
+
+    args.sem = obj;
+    ret = ioctl( device, WINESYNC_IOC_READ_SEM, &args );
+
+    if (ret < 0)
+        return errno_to_status( errno );
+    info->EventType = (args.flags & WINESYNC_SEM_GETONWAIT) ? SynchronizationEvent : NotificationEvent;
+    info->EventState = args.count;
+    return STATUS_SUCCESS;
+}
+
+
+static NTSTATUS fast_query_event( HANDLE handle, EVENT_BASIC_INFORMATION *info )
+{
+    struct fast_sync_cache_entry stack_cache, *cache;
+    NTSTATUS ret;
+    int device;
+
+    if ((device = get_fast_sync_device()) < 0)
+        return STATUS_NOT_IMPLEMENTED;
+
+    if ((ret = get_fast_sync_obj( handle, FAST_SYNC_EVENT, EVENT_QUERY_STATE,
+                                  &stack_cache, &cache )))
+        return ret;
+
+    ret = fast_query_event_obj( device, cache->obj, info );
+
+    release_fast_sync_obj( cache );
+    return ret;
+}
+
+
+static NTSTATUS fast_release_mutex_obj( int device, unsigned int obj, LONG *prev_count )
+{
+    struct winesync_mutex_args args = {0};
+    NTSTATUS ret;
+
+    args.mutex = obj;
+    args.owner = GetCurrentThreadId();
+    ret = ioctl( device, WINESYNC_IOC_PUT_MUTEX, &args );
+
+    if (ret < 0)
+    {
+        if (errno == EOVERFLOW)
+            return STATUS_MUTANT_LIMIT_EXCEEDED;
+        else if (errno == EPERM)
+            return STATUS_MUTANT_NOT_OWNED;
+        else
+            return errno_to_status( errno );
+    }
+    if (prev_count) *prev_count = 1 - args.count;
+    return STATUS_SUCCESS;
+}
+
+
+static NTSTATUS fast_release_mutex( HANDLE handle, LONG *prev_count )
+{
+    struct fast_sync_cache_entry stack_cache, *cache;
+    NTSTATUS ret;
+    int device;
+
+    if ((device = get_fast_sync_device()) < 0)
+        return STATUS_NOT_IMPLEMENTED;
+
+    if ((ret = get_fast_sync_obj( handle, FAST_SYNC_MUTEX, 0, &stack_cache, &cache )))
+        return ret;
+
+    ret = fast_release_mutex_obj( device, cache->obj, prev_count );
+
+    release_fast_sync_obj( cache );
+    return ret;
+}
+
+
+static NTSTATUS fast_query_mutex_obj( int device, unsigned int obj, MUTANT_BASIC_INFORMATION *info )
+{
+    struct winesync_mutex_args args = {0};
+    NTSTATUS ret;
+
+    args.mutex = obj;
+    ret = ioctl( device, WINESYNC_IOC_READ_MUTEX, &args );
+
+    if (ret < 0)
+    {
+        if (errno == EOWNERDEAD)
+        {
+            info->AbandonedState = TRUE;
+            info->OwnedByCaller = FALSE;
+            info->CurrentCount = 1;
+            return STATUS_SUCCESS;
+        }
+        else
+            return errno_to_status( errno );
+    }
+    info->AbandonedState = FALSE;
+    info->OwnedByCaller = (args.owner == GetCurrentThreadId());
+    info->CurrentCount = 1 - args.count;
+    return STATUS_SUCCESS;
+}
+
+
+static NTSTATUS fast_query_mutex( HANDLE handle, MUTANT_BASIC_INFORMATION *info )
+{
+    struct fast_sync_cache_entry stack_cache, *cache;
+    NTSTATUS ret;
+    int device;
+
+    if ((device = get_fast_sync_device()) < 0)
+        return STATUS_NOT_IMPLEMENTED;
+
+    if ((ret = get_fast_sync_obj( handle, FAST_SYNC_MUTEX, MUTANT_QUERY_STATE,
+                                  &stack_cache, &cache )))
+        return ret;
+
+    ret = fast_query_mutex_obj( device, cache->obj, info );
+
+    release_fast_sync_obj( cache );
+    return ret;
+}
+
+struct timespec64
+{
+    __s64 tv_sec;
+    __s64 tv_nsec;
+};
+
+static void timespec64_from_timeout( struct timespec64 *timespec, const LARGE_INTEGER *timeout )
+{
+    struct timespec now;
+    timeout_t relative;
+
+    clock_gettime( CLOCK_MONOTONIC, &now );
+
+    if (timeout->QuadPart <= 0)
+    {
+        relative = -timeout->QuadPart;
+    }
+    else
+    {
+        LARGE_INTEGER system_now;
+
+        /* the system clock is probably REALTIME, so we need to convert to
+         * relative time first */
+        NtQuerySystemTime( &system_now );
+        relative = timeout->QuadPart - system_now.QuadPart;
+    }
+
+    timespec->tv_sec = now.tv_sec + (relative / TICKSPERSEC);
+    timespec->tv_nsec = now.tv_nsec + ((relative % TICKSPERSEC) * 100);
+    if (timespec->tv_nsec >= 1000000000)
+    {
+        timespec->tv_nsec -= 1000000000;
+        ++timespec->tv_sec;
+    }
+}
+
+static void select_queue( HANDLE queue )
+{
+    SERVER_START_REQ( fast_select_queue )
+    {
+        req->handle = wine_server_obj_handle( queue );
+        wine_server_call( req );
+    }
+    SERVER_END_REQ;
+}
+
+static void unselect_queue( HANDLE queue, BOOL signaled )
+{
+    SERVER_START_REQ( fast_unselect_queue )
+    {
+        req->handle = wine_server_obj_handle( queue );
+        req->signaled = signaled;
+        wine_server_call( req );
+    }
+    SERVER_END_REQ;
+}
+
+static NTSTATUS fast_wait_objs( int device, DWORD count, const unsigned int *objs, BOOLEAN wait_any,
+                                BOOLEAN alertable, const LARGE_INTEGER *timeout, user_apc_t *apc )
+{
+    volatile struct winesync_wait_args args = {0};
+    struct timespec64 timespec;
+    uintptr_t timeout_ptr = 0;
+    unsigned long request;
+    NTSTATUS ret;
+
+    if (timeout && timeout->QuadPart != TIMEOUT_INFINITE)
+    {
+        timeout_ptr = (uintptr_t)&timespec;
+        timespec64_from_timeout( &timespec, timeout );
+    }
+    args.objs = (uintptr_t)objs;
+    args.count = count;
+    args.owner = GetCurrentThreadId();
+    args.index = ~0u;
+
+    if (wait_any || count == 1)
+        request = WINESYNC_IOC_WAIT_ANY;
+    else
+        request = WINESYNC_IOC_WAIT_ALL;
+
+    if (alertable)
+    {
+        struct timespec64 now64;
+        struct timespec now;
+
+        /* if there is an already signaled object and an APC available, the
+         * object is returned first */
+        clock_gettime( CLOCK_MONOTONIC, &now );
+        now64.tv_sec = now.tv_sec;
+        now64.tv_nsec = now.tv_nsec;
+        args.timeout = (uintptr_t)&now64;
+        do
+        {
+            ret = ioctl( device, request, &args );
+        } while (ret < 0 && errno == EINTR);
+
+        if (ret < 0 && errno == ETIMEDOUT)
+        {
+            args.timeout = timeout_ptr;
+
+            /* When a user APC is queued to this thread, the server wakes us
+             * with SIGUSR1, whereupon usr1_handler() will longjmp here, causing
+             * us to poll for a user APC again. It's not enough simply to retry
+             * on EINTR, as we might get SIGUSR1 after checking for user APCs
+             * but before calling ioctl(). */
+
+            sigsetjmp( ntdll_get_thread_data()->fast_alert_buf, 1 );
+
+            /* If the signal arrives *after* the ioctl, and the wait succeeded,
+             * we don't want to wait again. */
+
+            if (args.index != ~0u)
+            {
+                ntdll_get_thread_data()->in_fast_alert_wait = 0;
+                ret = 0;
+                goto out;
+            }
+
+            ntdll_get_thread_data()->in_fast_alert_wait = 1;
+
+            SERVER_START_REQ( check_user_apc )
+            {
+                ret = wine_server_call( req );
+            }
+            SERVER_END_REQ;
+
+            if (!ret)
+            {
+                ntdll_get_thread_data()->in_fast_alert_wait = 0;
+
+                /* Retrieve the user APC. We can't actually dequeue it until
+                 * after we reset in_fast_alert_wait, as otherwise we could
+                 * have the thread context changed on us and drop the APC data
+                 * on the floor. */
+                ret = server_select( NULL, 0, SELECT_INTERRUPTIBLE | SELECT_ALERTABLE,
+                                     0, NULL, NULL, apc );
+                assert( ret == STATUS_USER_APC );
+                return ret;
+            }
+
+            do
+            {
+                ret = ioctl( device, request, &args );
+            } while (ret < 0 && errno == EINTR);
+
+            ntdll_get_thread_data()->in_fast_alert_wait = 0;
+        }
+    }
+    else
     {
-        futex_wait( &supported, 10, NULL );
-        if (errno == ENOSYS)
+        args.timeout = timeout_ptr;
+        do
         {
-            futex_private = 0;
-            futex_wait( &supported, 10, NULL );
-        }
-        supported = (errno != ENOSYS);
+            ret = ioctl( device, request, &args );
+        } while (ret < 0 && errno == EINTR);
     }
-    return supported;
-}
 
-static int *get_futex(void **ptr)
-{
-    if (sizeof(void *) == 8)
-        return (int *)((((ULONG_PTR)ptr) + 3) & ~3);
-    else if (!(((ULONG_PTR)ptr) & 3))
-        return (int *)ptr;
+out:
+    if (!ret)
+        return wait_any ? args.index : 0;
+    else if (errno == EOWNERDEAD)
+        return STATUS_ABANDONED + (wait_any ? args.index : 0);
+    else if (errno == ETIMEDOUT)
+        return STATUS_TIMEOUT;
     else
-        return NULL;
+        return errno_to_status( errno );
 }
 
-static void timespec_from_timeout( struct timespec *timespec, const LARGE_INTEGER *timeout )
+static NTSTATUS fast_wait( DWORD count, const HANDLE *handles, BOOLEAN wait_any,
+                           BOOLEAN alertable, const LARGE_INTEGER *timeout )
 {
-    LARGE_INTEGER now;
-    timeout_t diff;
+    struct fast_sync_cache_entry stack_cache[64], *cache[64];
+    unsigned int objs[64];
+    HANDLE queue = NULL;
+    user_apc_t apc;
+    NTSTATUS ret;
+    DWORD i, j;
+    int device;
 
-    if (timeout->QuadPart > 0)
+    if ((device = get_fast_sync_device()) < 0)
+        return STATUS_NOT_IMPLEMENTED;
+
+    for (i = 0; i < count; ++i)
     {
-        NtQuerySystemTime( &now );
-        diff = timeout->QuadPart - now.QuadPart;
+        if ((ret = get_fast_sync_obj( handles[i], 0, SYNCHRONIZE, &stack_cache[i], &cache[i] )))
+        {
+            for (j = 0; j < i; ++j)
+                release_fast_sync_obj( cache[j] );
+            return ret;
+        }
+        if (cache[i]->type == FAST_SYNC_QUEUE)
+            queue = handles[i];
+
+        objs[i] = cache[i]->obj;
     }
-    else
-        diff = -timeout->QuadPart;
 
-    timespec->tv_sec  = diff / TICKSPERSEC;
-    timespec->tv_nsec = (diff % TICKSPERSEC) * 100;
-}
+    /* It's common to wait on the message queue alone. Some applications wait
+     * on it in fast paths, with a zero timeout. Since we take two server calls
+     * instead of one when going through fast_wait_objs(), and since we only
+     * need to go through that path if we're waiting on other objects, just
+     * delegate to the server if we're only waiting on the message queue. */
+    if (count == 1 && queue)
+    {
+        release_fast_sync_obj( cache[0] );
+        return server_wait_for_object( handles[0], alertable, timeout );
+    }
 
-#endif
+    if (queue) select_queue( queue );
 
+    ret = fast_wait_objs( device, count, objs, wait_any, alertable, timeout, &apc );
 
-static BOOL compare_addr( const void *addr, const void *cmp, SIZE_T size )
-{
-    switch (size)
-    {
-        case 1:
-            return (*(const UCHAR *)addr == *(const UCHAR *)cmp);
-        case 2:
-            return (*(const USHORT *)addr == *(const USHORT *)cmp);
-        case 4:
-            return (*(const ULONG *)addr == *(const ULONG *)cmp);
-        case 8:
-            return (*(const ULONG64 *)addr == *(const ULONG64 *)cmp);
-    }
+    if (queue) unselect_queue( queue, handles[ret] == queue );
 
-    return FALSE;
-}
+    for (i = 0; i < count; ++i)
+        release_fast_sync_obj( cache[i] );
 
+    if (ret == STATUS_USER_APC)
+        invoke_user_apc( NULL, &apc, ret );
+    return ret;
+}
 
-/* create a struct security_descriptor and contained information in one contiguous piece of memory */
-NTSTATUS alloc_object_attributes( const OBJECT_ATTRIBUTES *attr, struct object_attributes **ret,
-                                  data_size_t *ret_len )
+static NTSTATUS fast_signal_and_wait( HANDLE signal, HANDLE wait,
+                                      BOOLEAN alertable, const LARGE_INTEGER *timeout )
 {
-    unsigned int len = sizeof(**ret);
-    SID *owner = NULL, *group = NULL;
-    ACL *dacl = NULL, *sacl = NULL;
-    SECURITY_DESCRIPTOR *sd;
-
-    *ret = NULL;
-    *ret_len = 0;
+    struct fast_sync_cache_entry signal_stack_cache, *signal_cache;
+    struct fast_sync_cache_entry wait_stack_cache, *wait_cache;
+    HANDLE queue = NULL;
+    user_apc_t apc;
+    NTSTATUS ret;
+    int device;
 
-    if (!attr) return STATUS_SUCCESS;
+    if ((device = get_fast_sync_device()) < 0)
+        return STATUS_NOT_IMPLEMENTED;
 
-    if (attr->Length != sizeof(*attr)) return STATUS_INVALID_PARAMETER;
+    if ((ret = get_fast_sync_obj( signal, 0, 0, &signal_stack_cache, &signal_cache )))
+        return ret;
 
-    if ((sd = attr->SecurityDescriptor))
+    switch (signal_cache->type)
     {
-        len += sizeof(struct security_descriptor);
-	if (sd->Revision != SECURITY_DESCRIPTOR_REVISION) return STATUS_UNKNOWN_REVISION;
-        if (sd->Control & SE_SELF_RELATIVE)
-        {
-            SECURITY_DESCRIPTOR_RELATIVE *rel = (SECURITY_DESCRIPTOR_RELATIVE *)sd;
-            if (rel->Owner) owner = (PSID)((BYTE *)rel + rel->Owner);
-            if (rel->Group) group = (PSID)((BYTE *)rel + rel->Group);
-            if ((sd->Control & SE_SACL_PRESENT) && rel->Sacl) sacl = (PSID)((BYTE *)rel + rel->Sacl);
-            if ((sd->Control & SE_DACL_PRESENT) && rel->Dacl) dacl = (PSID)((BYTE *)rel + rel->Dacl);
-        }
-        else
-        {
-            owner = sd->Owner;
-            group = sd->Group;
-            if (sd->Control & SE_SACL_PRESENT) sacl = sd->Sacl;
-            if (sd->Control & SE_DACL_PRESENT) dacl = sd->Dacl;
-        }
+        case FAST_SYNC_SEMAPHORE:
+            if (!(signal_cache->access & SEMAPHORE_MODIFY_STATE))
+            {
+                release_fast_sync_obj( signal_cache );
+                return STATUS_ACCESS_DENIED;
+            }
+            break;
 
-        if (owner) len += offsetof( SID, SubAuthority[owner->SubAuthorityCount] );
-        if (group) len += offsetof( SID, SubAuthority[group->SubAuthorityCount] );
-        if (sacl) len += sacl->AclSize;
-        if (dacl) len += dacl->AclSize;
+        case FAST_SYNC_EVENT:
+            if (!(signal_cache->access & EVENT_MODIFY_STATE))
+            {
+                release_fast_sync_obj( signal_cache );
+                return STATUS_ACCESS_DENIED;
+            }
+            break;
 
-        /* fix alignment for the Unicode name that follows the structure */
-        len = (len + sizeof(WCHAR) - 1) & ~(sizeof(WCHAR) - 1);
+        case FAST_SYNC_MUTEX:
+            break;
+
+        default:
+            /* can't be signaled */
+            release_fast_sync_obj( signal_cache );
+            return STATUS_OBJECT_TYPE_MISMATCH;
     }
 
-    if (attr->ObjectName)
+    if ((ret = get_fast_sync_obj( wait, 0, SYNCHRONIZE, &wait_stack_cache, &wait_cache )))
     {
-        if (attr->ObjectName->Length & (sizeof(WCHAR) - 1)) return STATUS_OBJECT_NAME_INVALID;
-        len += attr->ObjectName->Length;
+        release_fast_sync_obj( signal_cache );
+        return ret;
     }
-    else if (attr->RootDirectory) return STATUS_OBJECT_NAME_INVALID;
-
-    len = (len + 3) & ~3;  /* DWORD-align the entire structure */
-
-    if (!(*ret = calloc( len, 1 ))) return STATUS_NO_MEMORY;
 
-    (*ret)->rootdir = wine_server_obj_handle( attr->RootDirectory );
-    (*ret)->attributes = attr->Attributes;
+    if (wait_cache->type == FAST_SYNC_QUEUE)
+        queue = wait;
 
-    if (attr->SecurityDescriptor)
+    switch (signal_cache->type)
     {
-        struct security_descriptor *descr = (struct security_descriptor *)(*ret + 1);
-        unsigned char *ptr = (unsigned char *)(descr + 1);
+        case FAST_SYNC_SEMAPHORE:
+            ret = fast_release_semaphore_obj( device, signal_cache->obj, 1, NULL );
+            break;
 
-        descr->control = sd->Control & ~SE_SELF_RELATIVE;
-        if (owner) descr->owner_len = offsetof( SID, SubAuthority[owner->SubAuthorityCount] );
-        if (group) descr->group_len = offsetof( SID, SubAuthority[group->SubAuthorityCount] );
-        if (sacl) descr->sacl_len = sacl->AclSize;
-        if (dacl) descr->dacl_len = dacl->AclSize;
+        case FAST_SYNC_EVENT:
+            ret = fast_set_event_obj( device, signal_cache->obj, NULL );
+            break;
 
-        memcpy( ptr, owner, descr->owner_len );
-        ptr += descr->owner_len;
-        memcpy( ptr, group, descr->group_len );
-        ptr += descr->group_len;
-        memcpy( ptr, sacl, descr->sacl_len );
-        ptr += descr->sacl_len;
-        memcpy( ptr, dacl, descr->dacl_len );
-        (*ret)->sd_len = (sizeof(*descr) + descr->owner_len + descr->group_len + descr->sacl_len +
-                          descr->dacl_len + sizeof(WCHAR) - 1) & ~(sizeof(WCHAR) - 1);
+        case FAST_SYNC_MUTEX:
+            ret = fast_release_mutex_obj( device, signal_cache->obj, NULL );
+            break;
+
+        default:
+            assert( 0 );
+            break;
     }
 
-    if (attr->ObjectName)
+    if (!ret)
     {
-        unsigned char *ptr = (unsigned char *)(*ret + 1) + (*ret)->sd_len;
-        (*ret)->name_len = attr->ObjectName->Length;
-        memcpy( ptr, attr->ObjectName->Buffer, (*ret)->name_len );
+        if (queue) select_queue( queue );
+
+        ret = fast_wait_objs( device, 1, &wait_cache->obj, TRUE, alertable, timeout, &apc );
+
+        if (queue) unselect_queue( queue, !ret );
     }
 
-    *ret_len = len;
-    return STATUS_SUCCESS;
+    release_fast_sync_obj( signal_cache );
+    release_fast_sync_obj( wait_cache );
+
+    if (ret == STATUS_USER_APC)
+        invoke_user_apc( NULL, &apc, ret );
+    return ret;
 }
 
+#else
 
-static NTSTATUS validate_open_object_attributes( const OBJECT_ATTRIBUTES *attr )
+void close_fast_sync_obj( HANDLE handle )
 {
-    if (!attr || attr->Length != sizeof(*attr)) return STATUS_INVALID_PARAMETER;
+}
 
-    if (attr->ObjectName)
-    {
-        if (attr->ObjectName->Length & (sizeof(WCHAR) - 1)) return STATUS_OBJECT_NAME_INVALID;
-    }
-    else if (attr->RootDirectory) return STATUS_OBJECT_NAME_INVALID;
+static NTSTATUS fast_release_semaphore( HANDLE handle, ULONG count, ULONG *prev_count )
+{
+    return STATUS_NOT_IMPLEMENTED;
+}
 
-    return STATUS_SUCCESS;
+static NTSTATUS fast_query_semaphore( HANDLE handle, SEMAPHORE_BASIC_INFORMATION *info )
+{
+    return STATUS_NOT_IMPLEMENTED;
+}
+
+static NTSTATUS fast_set_event( HANDLE handle, LONG *prev_state )
+{
+    return STATUS_NOT_IMPLEMENTED;
+}
+
+static NTSTATUS fast_reset_event( HANDLE handle, LONG *prev_state )
+{
+    return STATUS_NOT_IMPLEMENTED;
+}
+
+static NTSTATUS fast_pulse_event( HANDLE handle, LONG *prev_state )
+{
+    return STATUS_NOT_IMPLEMENTED;
+}
+
+static NTSTATUS fast_query_event( HANDLE handle, EVENT_BASIC_INFORMATION *info )
+{
+    return STATUS_NOT_IMPLEMENTED;
+}
+
+static NTSTATUS fast_release_mutex( HANDLE handle, LONG *prev_count )
+{
+    return STATUS_NOT_IMPLEMENTED;
+}
+
+static NTSTATUS fast_query_mutex( HANDLE handle, MUTANT_BASIC_INFORMATION *info )
+{
+    return STATUS_NOT_IMPLEMENTED;
 }
 
+static NTSTATUS fast_wait( DWORD count, const HANDLE *handles, BOOLEAN wait_any,
+                           BOOLEAN alertable, const LARGE_INTEGER *timeout )
+{
+    return STATUS_NOT_IMPLEMENTED;
+}
+
+static NTSTATUS fast_signal_and_wait( HANDLE signal, HANDLE wait,
+                                      BOOLEAN alertable, const LARGE_INTEGER *timeout )
+{
+    return STATUS_NOT_IMPLEMENTED;
+}
+
+#endif
+
 
 /******************************************************************************
  *              NtCreateSemaphore (NTDLL.@)
@@ -319,6 +1350,9 @@ NTSTATUS WINAPI NtCreateSemaphore( HANDLE *handle, ACCESS_MASK access, const OBJ
     data_size_t len;
     struct object_attributes *objattr;
 
+    TRACE( "access %#x, name %s, initial %d, max %d\n", access,
+           attr ? debugstr_us(attr->ObjectName) : "(null)", initial, max );
+
     if (max <= 0 || initial < 0 || initial > max) return STATUS_INVALID_PARAMETER;
     if ((ret = alloc_object_attributes( attr, &objattr, &len ))) return ret;
 
@@ -345,6 +1379,8 @@ NTSTATUS WINAPI NtOpenSemaphore( HANDLE *handle, ACCESS_MASK access, const OBJEC
 {
     NTSTATUS ret;
 
+    TRACE( "access %#x, name %s\n", access, attr ? debugstr_us(attr->ObjectName) : "(null)" );
+
     if ((ret = validate_open_object_attributes( attr ))) return ret;
 
     SERVER_START_REQ( open_semaphore )
@@ -381,6 +1417,12 @@ NTSTATUS WINAPI NtQuerySemaphore( HANDLE handle, SEMAPHORE_INFORMATION_CLASS cla
 
     if (len != sizeof(SEMAPHORE_BASIC_INFORMATION)) return STATUS_INFO_LENGTH_MISMATCH;
 
+    if ((ret = fast_query_semaphore( handle, out )) != STATUS_NOT_IMPLEMENTED)
+    {
+        if (!ret && ret_len) *ret_len = sizeof(SEMAPHORE_BASIC_INFORMATION);
+        return ret;
+    }
+
     SERVER_START_REQ( query_semaphore )
     {
         req->handle = wine_server_obj_handle( handle );
@@ -403,6 +1445,11 @@ NTSTATUS WINAPI NtReleaseSemaphore( HANDLE handle, ULONG count, ULONG *previous
 {
     NTSTATUS ret;
 
+    TRACE( "handle %p, count %u, prev_count %p\n", handle, count, previous );
+
+    if ((ret = fast_release_semaphore( handle, count, previous )) != STATUS_NOT_IMPLEMENTED)
+        return ret;
+
     SERVER_START_REQ( release_semaphore )
     {
         req->handle = wine_server_obj_handle( handle );
@@ -427,6 +1474,9 @@ NTSTATUS WINAPI NtCreateEvent( HANDLE *handle, ACCESS_MASK access, const OBJECT_
     data_size_t len;
     struct object_attributes *objattr;
 
+    TRACE( "access %#x, name %s, type %u, state %u\n", access,
+           attr ? debugstr_us(attr->ObjectName) : "(null)", type, state );
+
     if (type != NotificationEvent && type != SynchronizationEvent) return STATUS_INVALID_PARAMETER;
     if ((ret = alloc_object_attributes( attr, &objattr, &len ))) return ret;
 
@@ -453,6 +1503,8 @@ NTSTATUS WINAPI NtOpenEvent( HANDLE *handle, ACCESS_MASK access, const OBJECT_AT
 {
     NTSTATUS ret;
 
+    TRACE( "access %#x, name %s\n", access, attr ? debugstr_us(attr->ObjectName) : "(null)" );
+
     if ((ret = validate_open_object_attributes( attr ))) return ret;
 
     SERVER_START_REQ( open_event )
@@ -477,6 +1529,11 @@ NTSTATUS WINAPI NtSetEvent( HANDLE handle, LONG *prev_state )
 {
     NTSTATUS ret;
 
+    TRACE( "handle %p, prev_state %p\n", handle, prev_state );
+
+    if ((ret = fast_set_event( handle, prev_state )) != STATUS_NOT_IMPLEMENTED)
+        return ret;
+
     SERVER_START_REQ( event_op )
     {
         req->handle = wine_server_obj_handle( handle );
@@ -496,6 +1553,11 @@ NTSTATUS WINAPI NtResetEvent( HANDLE handle, LONG *prev_state )
 {
     NTSTATUS ret;
 
+    TRACE( "handle %p, prev_state %p\n", handle, prev_state );
+
+    if ((ret = fast_reset_event( handle, prev_state )) != STATUS_NOT_IMPLEMENTED)
+        return ret;
+
     SERVER_START_REQ( event_op )
     {
         req->handle = wine_server_obj_handle( handle );
@@ -525,6 +1587,11 @@ NTSTATUS WINAPI NtPulseEvent( HANDLE handle, LONG *prev_state )
 {
     NTSTATUS ret;
 
+    TRACE( "handle %p, prev_state %p\n", handle, prev_state );
+
+    if ((ret = fast_pulse_event( handle, prev_state )) != STATUS_NOT_IMPLEMENTED)
+        return ret;
+
     SERVER_START_REQ( event_op )
     {
         req->handle = wine_server_obj_handle( handle );
@@ -557,6 +1624,12 @@ NTSTATUS WINAPI NtQueryEvent( HANDLE handle, EVENT_INFORMATION_CLASS class,
 
     if (len != sizeof(EVENT_BASIC_INFORMATION)) return STATUS_INFO_LENGTH_MISMATCH;
 
+    if ((ret = fast_query_event( handle, out )) != STATUS_NOT_IMPLEMENTED)
+    {
+        if (!ret && ret_len) *ret_len = sizeof(EVENT_BASIC_INFORMATION);
+        return ret;
+    }
+
     SERVER_START_REQ( query_event )
     {
         req->handle = wine_server_obj_handle( handle );
@@ -582,6 +1655,9 @@ NTSTATUS WINAPI NtCreateMutant( HANDLE *handle, ACCESS_MASK access, const OBJECT
     data_size_t len;
     struct object_attributes *objattr;
 
+    TRACE( "access %#x, name %s, owned %u\n", access,
+           attr ? debugstr_us(attr->ObjectName) : "(null)", owned );
+
     if ((ret = alloc_object_attributes( attr, &objattr, &len ))) return ret;
 
     SERVER_START_REQ( create_mutex )
@@ -606,6 +1682,8 @@ NTSTATUS WINAPI NtOpenMutant( HANDLE *handle, ACCESS_MASK access, const OBJECT_A
 {
     NTSTATUS ret;
 
+    TRACE( "access %#x, name %s\n", access, attr ? debugstr_us(attr->ObjectName) : "(null)" );
+
     if ((ret = validate_open_object_attributes( attr ))) return ret;
 
     SERVER_START_REQ( open_mutex )
@@ -630,6 +1708,11 @@ NTSTATUS WINAPI NtReleaseMutant( HANDLE handle, LONG *prev_count )
 {
     NTSTATUS ret;
 
+    TRACE( "handle %p, prev_count %p\n", handle, prev_count );
+
+    if ((ret = fast_release_mutex( handle, prev_count )) != STATUS_NOT_IMPLEMENTED)
+        return ret;
+
     SERVER_START_REQ( release_mutex )
     {
         req->handle = wine_server_obj_handle( handle );
@@ -660,6 +1743,12 @@ NTSTATUS WINAPI NtQueryMutant( HANDLE handle, MUTANT_INFORMATION_CLASS class,
 
     if (len != sizeof(MUTANT_BASIC_INFORMATION)) return STATUS_INFO_LENGTH_MISMATCH;
 
+    if ((ret = fast_query_mutex( handle, out )) != STATUS_NOT_IMPLEMENTED)
+    {
+        if (!ret && ret_len) *ret_len = sizeof(MUTANT_BASIC_INFORMATION);
+        return ret;
+    }
+
     SERVER_START_REQ( query_mutex )
     {
         req->handle = wine_server_obj_handle( handle );
@@ -1277,6 +2366,9 @@ NTSTATUS WINAPI NtCreateTimer( HANDLE *handle, ACCESS_MASK access, const OBJECT_
     data_size_t len;
     struct object_attributes *objattr;
 
+    TRACE( "access %#x, name %s, type %u\n", access,
+           attr ? debugstr_us(attr->ObjectName) : "(null)", type );
+
     if (type != NotificationTimer && type != SynchronizationTimer) return STATUS_INVALID_PARAMETER;
 
     if ((ret = alloc_object_attributes( attr, &objattr, &len ))) return ret;
@@ -1304,6 +2396,8 @@ NTSTATUS WINAPI NtOpenTimer( HANDLE *handle, ACCESS_MASK access, const OBJECT_AT
 {
     NTSTATUS ret;
 
+    TRACE( "access %#x, name %s\n", access, attr ? debugstr_us(attr->ObjectName) : "(null)" );
+
     if ((ret = validate_open_object_attributes( attr ))) return ret;
 
     SERVER_START_REQ( open_timer )
@@ -1356,6 +2450,8 @@ NTSTATUS WINAPI NtCancelTimer( HANDLE handle, BOOLEAN *state )
 {
     NTSTATUS ret;
 
+    TRACE( "handle %p, state %p\n", handle, state );
+
     SERVER_START_REQ( cancel_timer )
     {
         req->handle = wine_server_obj_handle( handle );
@@ -1424,13 +2520,29 @@ NTSTATUS WINAPI NtWaitForMultipleObjects( DWORD count, const HANDLE *handles, BO
 {
     select_op_t select_op;
     UINT i, flags = SELECT_INTERRUPTIBLE;
+    NTSTATUS ret;
 
     if (!count || count > MAXIMUM_WAIT_OBJECTS) return STATUS_INVALID_PARAMETER_1;
 
+    if (TRACE_ON(sync))
+    {
+        TRACE( "wait_any %u, alertable %u, handles {%p", wait_any, alertable, handles[0] );
+        for (i = 1; i < count; i++) TRACE( ", %p", handles[i] );
+        TRACE( "}, timeout %s\n", debugstr_timeout(timeout) );
+    }
+
+    if ((ret = fast_wait( count, handles, wait_any, alertable, timeout )) != STATUS_NOT_IMPLEMENTED)
+    {
+        TRACE( "-> %#x\n", ret );
+        return ret;
+    }
+
     if (alertable) flags |= SELECT_ALERTABLE;
     select_op.wait.op = wait_any ? SELECT_WAIT : SELECT_WAIT_ALL;
     for (i = 0; i < count; i++) select_op.wait.handles[i] = wine_server_obj_handle( handles[i] );
-    return server_wait( &select_op, offsetof( select_op_t, wait.handles[count] ), flags, timeout );
+    ret = server_wait( &select_op, offsetof( select_op_t, wait.handles[count] ), flags, timeout );
+    TRACE( "-> %#x\n", ret );
+    return ret;
 }
 
 
@@ -1451,9 +2563,15 @@ NTSTATUS WINAPI NtSignalAndWaitForSingleObject( HANDLE signal, HANDLE wait,
 {
     select_op_t select_op;
     UINT flags = SELECT_INTERRUPTIBLE;
+    NTSTATUS ret;
+
+    TRACE( "signal %p, wait %p, alertable %u, timeout %s\n", signal, wait, alertable, debugstr_timeout(timeout) );
 
     if (!signal) return STATUS_INVALID_HANDLE;
 
+    if ((ret = fast_signal_and_wait( signal, wait, alertable, timeout )) != STATUS_NOT_IMPLEMENTED)
+        return ret;
+
     if (alertable) flags |= SELECT_ALERTABLE;
     select_op.signal_and_wait.op = SELECT_SIGNAL_AND_WAIT;
     select_op.signal_and_wait.wait = wine_server_obj_handle( wait );
@@ -1481,6 +2599,8 @@ NTSTATUS WINAPI NtYieldExecution(void)
  */
 NTSTATUS WINAPI NtDelayExecution( BOOLEAN alertable, const LARGE_INTEGER *timeout )
 {
+//    TRACE( "alertable %u, timeout %s\n", alertable, debugstr_timeout(timeout) );
+
     /* if alertable, we need to query the server */
     if (alertable) return server_wait( NULL, 0, SELECT_INTERRUPTIBLE | SELECT_ALERTABLE, timeout );
 
@@ -1651,6 +2771,9 @@ NTSTATUS WINAPI NtCreateKeyedEvent( HANDLE *handle, ACCESS_MASK access,
     data_size_t len;
     struct object_attributes *objattr;
 
+    TRACE( "access %#x, name %s, flags %#x\n", access,
+           attr ? debugstr_us(attr->ObjectName) : "(null)", flags );
+
     if ((ret = alloc_object_attributes( attr, &objattr, &len ))) return ret;
 
     SERVER_START_REQ( create_keyed_event )
@@ -1674,6 +2797,8 @@ NTSTATUS WINAPI NtOpenKeyedEvent( HANDLE *handle, ACCESS_MASK access, const OBJE
 {
     NTSTATUS ret;
 
+    TRACE( "access %#x, name %s\n", access, attr ? debugstr_us(attr->ObjectName) : "(null)" );
+
     if ((ret = validate_open_object_attributes( attr ))) return ret;
 
     SERVER_START_REQ( open_keyed_event )
@@ -1699,6 +2824,8 @@ NTSTATUS WINAPI NtWaitForKeyedEvent( HANDLE handle, const void *key,
     select_op_t select_op;
     UINT flags = SELECT_INTERRUPTIBLE;
 
+    TRACE( "handle %p, key %p, alertable %u, timeout %s\n", handle, key, alertable, debugstr_timeout(timeout) );
+
     if (!handle) handle = keyed_event;
     if ((ULONG_PTR)key & 1) return STATUS_INVALID_PARAMETER_1;
     if (alertable) flags |= SELECT_ALERTABLE;
@@ -1718,6 +2845,8 @@ NTSTATUS WINAPI NtReleaseKeyedEvent( HANDLE handle, const void *key,
     select_op_t select_op;
     UINT flags = SELECT_INTERRUPTIBLE;
 
+    TRACE( "handle %p, key %p, alertable %u, timeout %s\n", handle, key, alertable, debugstr_timeout(timeout) );
+
     if (!handle) handle = keyed_event;
     if ((ULONG_PTR)key & 1) return STATUS_INVALID_PARAMETER_1;
     if (alertable) flags |= SELECT_ALERTABLE;
diff --git a/dlls/ntdll/unix/thread.c b/dlls/ntdll/unix/thread.c
index 54b748e99cb..d7b850d8746 100644
--- a/dlls/ntdll/unix/thread.c
+++ b/dlls/ntdll/unix/thread.c
@@ -1354,7 +1354,7 @@ NTSTATUS get_thread_context( HANDLE handle, void *context, BOOL *self, USHORT ma
 
     if (ret == STATUS_PENDING)
     {
-        NtWaitForSingleObject( context_handle, FALSE, NULL );
+        server_wait_for_object( context_handle, FALSE, NULL );
 
         SERVER_START_REQ( get_thread_context )
         {
diff --git a/dlls/ntdll/unix/unix_private.h b/dlls/ntdll/unix/unix_private.h
index 5ebbc6d702b..6e3bff4ba9e 100644
--- a/dlls/ntdll/unix/unix_private.h
+++ b/dlls/ntdll/unix/unix_private.h
@@ -22,6 +22,7 @@
 #define __NTDLL_UNIX_PRIVATE_H
 
 #include <pthread.h>
+#include <setjmp.h>
 #include <signal.h>
 #include "unixlib.h"
 #include "wine/server.h"
@@ -69,6 +70,8 @@ struct ntdll_thread_data
     PRTL_THREAD_START_ROUTINE start;  /* thread entry point */
     void              *param;         /* thread entry point parameter */
     void              *jmp_buf;       /* setjmp buffer for exception handling */
+    volatile int       in_fast_alert_wait; /* are we currently in a fast alertable wait? */
+    sigjmp_buf         fast_alert_buf; /* setjmp buffer to restart a fast alertable wait */
 };
 
 C_ASSERT( sizeof(struct ntdll_thread_data) <= sizeof(((TEB *)0)->GdiTebBatch) );
@@ -168,5 +171,8 @@ extern NTSTATUS load_start_exe( WCHAR **image, void **module ) DECLSPEC_HIDDEN;
 extern void start_server( BOOL debug ) DECLSPEC_HIDDEN;
 
+extern pthread_mutex_t fd_cache_mutex DECLSPEC_HIDDEN;
+
+extern NTSTATUS invoke_user_apc( CONTEXT *context, const user_apc_t *apc, NTSTATUS status ) DECLSPEC_HIDDEN;
 extern unsigned int server_call_unlocked( void *req_ptr ) DECLSPEC_HIDDEN;
 extern void server_enter_uninterrupted_section( pthread_mutex_t *mutex, sigset_t *sigset ) DECLSPEC_HIDDEN;
 extern void server_leave_uninterrupted_section( pthread_mutex_t *mutex, sigset_t *sigset ) DECLSPEC_HIDDEN;
@@ -176,6 +182,8 @@ extern unsigned int server_select( const select_op_t *select_op, data_size_t siz
                                    user_apc_t *user_apc ) DECLSPEC_HIDDEN;
 extern unsigned int server_wait( const select_op_t *select_op, data_size_t size, UINT flags,
                                  const LARGE_INTEGER *timeout ) DECLSPEC_HIDDEN;
+extern unsigned int server_wait_for_object( HANDLE handle, BOOL alertable,
+                                            const LARGE_INTEGER *timeout ) DECLSPEC_HIDDEN;
 extern unsigned int server_queue_process_apc( HANDLE process, const apc_call_t *call,
                                               apc_result_t *result ) DECLSPEC_HIDDEN;
 extern int server_get_unix_fd( HANDLE handle, unsigned int wanted_access, int *unix_fd,
@@ -284,6 +292,8 @@ extern void add_completion( HANDLE handle, ULONG_PTR value, NTSTATUS status, ULO
 
 extern void dbg_init(void) DECLSPEC_HIDDEN;
 
+extern void close_fast_sync_obj( HANDLE handle ) DECLSPEC_HIDDEN;
+
 extern NTSTATUS call_user_apc_dispatcher( CONTEXT *context_ptr, ULONG_PTR arg1, ULONG_PTR arg2, ULONG_PTR arg3,
                                           PNTAPCFUNC func, NTSTATUS status ) DECLSPEC_HIDDEN;
 extern NTSTATUS call_user_exception_dispatcher( EXCEPTION_RECORD *rec, CONTEXT *context ) DECLSPEC_HIDDEN;
diff --git a/include/config.h.in b/include/config.h.in
index 68122959035..c5e1d4a921b 100644
--- a/include/config.h.in
+++ b/include/config.h.in
@@ -396,6 +396,9 @@
 /* Define to 1 if you have the <linux/videodev2.h> header file. */
 #undef HAVE_LINUX_VIDEODEV2_H
 
+/* Define to 1 if you have the <linux/winesync.h> header file. */
+#undef HAVE_LINUX_WINESYNC_H
+
 /* Define to 1 if you have the `lstat' function. */
 #undef HAVE_LSTAT
 
diff --git a/include/wine/server_protocol.h b/include/wine/server_protocol.h
index fe1f5394a72..0c877db8fde 100644
--- a/include/wine/server_protocol.h
+++ b/include/wine/server_protocol.h
@@ -5448,6 +5448,84 @@ struct get_next_thread_reply
 };
 
 
+enum fast_sync_type
+{
+    FAST_SYNC_SEMAPHORE = 1,
+    FAST_SYNC_MUTEX,
+    FAST_SYNC_EVENT,
+    FAST_SYNC_SERVER,
+    FAST_SYNC_QUEUE,
+};
+
+
+
+struct get_fast_sync_device_request
+{
+    struct request_header __header;
+    char __pad_12[4];
+};
+struct get_fast_sync_device_reply
+{
+    struct reply_header __header;
+    obj_handle_t handle;
+    char __pad_12[4];
+};
+
+
+
+struct get_fast_sync_obj_request
+{
+    struct request_header __header;
+    obj_handle_t handle;
+};
+struct get_fast_sync_obj_reply
+{
+    struct reply_header __header;
+    obj_handle_t handle;
+    int          obj;
+    int          type;
+    unsigned int access;
+};
+
+
+
+struct fast_select_queue_request
+{
+    struct request_header __header;
+    obj_handle_t handle;
+};
+struct fast_select_queue_reply
+{
+    struct reply_header __header;
+};
+
+
+
+struct fast_unselect_queue_request
+{
+    struct request_header __header;
+    obj_handle_t handle;
+    int          signaled;
+    char __pad_20[4];
+};
+struct fast_unselect_queue_reply
+{
+    struct reply_header __header;
+};
+
+
+
+struct check_user_apc_request
+{
+    struct request_header __header;
+    char __pad_12[4];
+};
+struct check_user_apc_reply
+{
+    struct reply_header __header;
+};
+
+
 enum request
 {
     REQ_new_process,
@@ -5726,6 +5804,11 @@ enum request
     REQ_suspend_process,
     REQ_resume_process,
     REQ_get_next_thread,
+    REQ_get_fast_sync_device,
+    REQ_get_fast_sync_obj,
+    REQ_fast_select_queue,
+    REQ_fast_unselect_queue,
+    REQ_check_user_apc,
     REQ_NB_REQUESTS
 };
 
@@ -6009,6 +6092,11 @@ union generic_request
     struct suspend_process_request suspend_process_request;
     struct resume_process_request resume_process_request;
     struct get_next_thread_request get_next_thread_request;
+    struct get_fast_sync_device_request get_fast_sync_device_request;
+    struct get_fast_sync_obj_request get_fast_sync_obj_request;
+    struct fast_select_queue_request fast_select_queue_request;
+    struct fast_unselect_queue_request fast_unselect_queue_request;
+    struct check_user_apc_request check_user_apc_request;
 };
 union generic_reply
 {
@@ -6290,6 +6378,11 @@ union generic_reply
     struct suspend_process_reply suspend_process_reply;
     struct resume_process_reply resume_process_reply;
     struct get_next_thread_reply get_next_thread_reply;
+    struct get_fast_sync_device_reply get_fast_sync_device_reply;
+    struct get_fast_sync_obj_reply get_fast_sync_obj_reply;
+    struct fast_select_queue_reply fast_select_queue_reply;
+    struct fast_unselect_queue_reply fast_unselect_queue_reply;
+    struct check_user_apc_reply check_user_apc_reply;
 };
 
 /* ### protocol_version begin ### */
diff --git a/server/Makefile.in b/server/Makefile.in
index 4264e3db108..7486ef5010d 100644
--- a/server/Makefile.in
+++ b/server/Makefile.in
@@ -12,6 +12,7 @@ C_SRCS = \
 	device.c \
 	directory.c \
 	event.c \
+	fast_sync.c \
 	fd.c \
 	file.c \
 	handle.c \
diff --git a/server/async.c b/server/async.c
index 4dedb27f3d8..ad109fbbc05 100644
--- a/server/async.c
+++ b/server/async.c
@@ -84,6 +84,7 @@ static const struct object_ops async_ops =
     NULL,                      /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    no_get_fast_sync,          /* get_fast_sync */
     no_close_handle,           /* close_handle */
     async_destroy              /* destroy */
 };
@@ -506,6 +507,7 @@ static const struct object_ops iosb_ops =
     NULL,                     /* unlink_name */
     no_open_file,             /* open_file */
     no_kernel_obj_list,       /* get_kernel_obj_list */
+    no_get_fast_sync,         /* get_fast_sync */
     no_close_handle,          /* close_handle */
     iosb_destroy              /* destroy */
 };
diff --git a/server/atom.c b/server/atom.c
index 8d0ffbb05f3..e638b064f49 100644
--- a/server/atom.c
+++ b/server/atom.c
@@ -92,6 +92,7 @@ static const struct object_ops atom_table_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_get_fast_sync,             /* get_fast_sync */
     no_close_handle,              /* close_handle */
     atom_table_destroy            /* destroy */
 };
diff --git a/server/change.c b/server/change.c
index b02a9cd65bf..0eadae4e96d 100644
--- a/server/change.c
+++ b/server/change.c
@@ -126,6 +126,7 @@ static const struct object_ops dir_ops =
     NULL,                     /* unlink_name */
     no_open_file,             /* open_file */
     no_kernel_obj_list,       /* get_kernel_obj_list */
+    default_fd_get_fast_sync, /* get_fast_sync */
     dir_close_handle,         /* close_handle */
     dir_destroy               /* destroy */
 };
diff --git a/server/clipboard.c b/server/clipboard.c
index 1c4875ff726..1d9369deb52 100644
--- a/server/clipboard.c
+++ b/server/clipboard.c
@@ -89,6 +89,7 @@ static const struct object_ops clipboard_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_get_fast_sync,             /* get_fast_sync */
     no_close_handle,              /* close_handle */
     clipboard_destroy             /* destroy */
 };
diff --git a/server/completion.c b/server/completion.c
index eb0d256ad09..776095b3900 100644
--- a/server/completion.c
+++ b/server/completion.c
@@ -62,10 +62,12 @@ struct completion
     struct object  obj;
     struct list    queue;
     unsigned int   depth;
+    struct fast_sync *fast_sync;
 };
 
 static void completion_dump( struct object*, int );
 static int completion_signaled( struct object *obj, struct wait_queue_entry *entry );
+static struct fast_sync *completion_get_fast_sync( struct object *obj );
 static void completion_destroy( struct object * );
 
 static const struct object_ops completion_ops =
@@ -88,6 +90,7 @@ static const struct object_ops completion_ops =
     default_unlink_name,       /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    completion_get_fast_sync,  /* get_fast_sync */
     no_close_handle,           /* close_handle */
     completion_destroy         /* destroy */
 };
@@ -110,6 +113,7 @@ static void completion_destroy( struct object *obj)
     {
         free( tmp );
     }
+    if (completion->fast_sync) release_object( completion->fast_sync );
 }
 
 static void completion_dump( struct object *obj, int verbose )
@@ -127,6 +131,16 @@ static int completion_signaled( struct object *obj, struct wait_queue_entry *ent
     return !list_empty( &completion->queue );
 }
 
+static struct fast_sync *completion_get_fast_sync( struct object *obj )
+{
+    struct completion *completion = (struct completion *)obj;
+
+    if (!completion->fast_sync)
+        completion->fast_sync = fast_create_event( FAST_SYNC_SERVER, 1, !list_empty( &completion->queue ) );
+    if (completion->fast_sync) grab_object( completion->fast_sync );
+    return completion->fast_sync;
+}
+
 static struct completion *create_completion( struct object *root, const struct unicode_str *name,
                                              unsigned int attr, unsigned int concurrent,
                                              const struct security_descriptor *sd )
@@ -139,6 +153,7 @@ static struct completion *create_completion( struct object *root, const struct u
         {
             list_init( &completion->queue );
             completion->depth = 0;
+            completion->fast_sync = NULL;
         }
     }
 
@@ -166,6 +181,7 @@ void add_completion( struct completion *completion, apc_param_t ckey, apc_param_
     list_add_tail( &completion->queue, &msg->queue_entry );
     completion->depth++;
     wake_up( &completion->obj, 1 );
+    fast_set_event( completion->fast_sync );
 }
 
 /* create a completion */
@@ -232,6 +248,8 @@ DECL_HANDLER(remove_completion)
         reply->status = msg->status;
         reply->information = msg->information;
         free( msg );
+        if (list_empty( &completion->queue ))
+            fast_reset_event( completion->fast_sync );
     }
 
     release_object( completion );
diff --git a/server/console.c b/server/console.c
index 1e6f6c0f8a3..a6d192394eb 100644
--- a/server/console.c
+++ b/server/console.c
@@ -62,6 +62,7 @@ struct console
     struct fd                   *fd;            /* for bare console, attached input fd */
     struct async_queue           ioctl_q;       /* ioctl queue */
     struct async_queue           read_q;        /* read queue */
+    struct fast_sync            *fast_sync;     /* fast synchronization object */
 };
 
 static void console_dump( struct object *obj, int verbose );
@@ -72,6 +73,7 @@ static struct object *console_lookup_name( struct object *obj, struct unicode_st
                                            unsigned int attr, struct object *root );
 static struct object *console_open_file( struct object *obj, unsigned int access,
                                          unsigned int sharing, unsigned int options );
+static struct fast_sync *console_get_fast_sync( struct object *obj );
 
 static const struct object_ops console_ops =
 {
@@ -93,6 +95,7 @@ static const struct object_ops console_ops =
     NULL,                             /* unlink_name */
     console_open_file,                /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    console_get_fast_sync,            /* get_fast_sync */
     no_close_handle,                  /* close_handle */
     console_destroy                   /* destroy */
 };
@@ -137,6 +140,7 @@ struct console_server
     int                   busy;        /* flag if server processing an ioctl */
     int                   term_fd;     /* UNIX terminal fd */
     struct termios        termios;     /* original termios */
+    struct fast_sync     *fast_sync;   /* fast synchronization object */
 };
 
 static void console_server_dump( struct object *obj, int verbose );
@@ -147,6 +151,7 @@ static struct object *console_server_lookup_name( struct object *obj, struct uni
                                                 unsigned int attr, struct object *root );
 static struct object *console_server_open_file( struct object *obj, unsigned int access,
                                                 unsigned int sharing, unsigned int options );
+static struct fast_sync *console_server_get_fast_sync( struct object *obj );
 
 static const struct object_ops console_server_ops =
 {
@@ -168,6 +173,7 @@ static const struct object_ops console_server_ops =
     NULL,                             /* unlink_name */
     console_server_open_file,         /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    console_server_get_fast_sync,     /* get_fast_sync */
     no_close_handle,                  /* close_handle */
     console_server_destroy            /* destroy */
 };
@@ -215,6 +221,7 @@ static int screen_buffer_add_queue( struct object *obj, struct wait_queue_entry
 static struct fd *screen_buffer_get_fd( struct object *obj );
 static struct object *screen_buffer_open_file( struct object *obj, unsigned int access,
                                                unsigned int sharing, unsigned int options );
+static struct fast_sync *screen_buffer_get_fast_sync( struct object *obj );
 
 static const struct object_ops screen_buffer_ops =
 {
@@ -236,6 +243,7 @@ static const struct object_ops screen_buffer_ops =
     NULL,                             /* unlink_name */
     screen_buffer_open_file,          /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    screen_buffer_get_fast_sync,      /* get_fast_sync */
     no_close_handle,                  /* close_handle */
     screen_buffer_destroy             /* destroy */
 };
@@ -284,6 +292,7 @@ static const struct object_ops console_device_ops =
     default_unlink_name,              /* unlink_name */
     console_device_open_file,         /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_get_fast_sync,                 /* get_fast_sync */
     no_close_handle,                  /* close_handle */
     no_destroy                        /* destroy */
 };
@@ -299,6 +308,7 @@ static struct object *console_input_open_file( struct object *obj, unsigned int
                                                unsigned int sharing, unsigned int options );
 static int console_input_add_queue( struct object *obj, struct wait_queue_entry *entry );
 static struct fd *console_input_get_fd( struct object *obj );
+static struct fast_sync *console_input_get_fast_sync( struct object *obj );
 static void console_input_destroy( struct object *obj );
 
 static const struct object_ops console_input_ops =
@@ -321,6 +331,7 @@ static const struct object_ops console_input_ops =
     default_unlink_name,              /* unlink_name */
     console_input_open_file,          /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    console_input_get_fast_sync,      /* get_fast_sync */
     no_close_handle,                  /* close_handle */
     console_input_destroy             /* destroy */
 };
@@ -355,6 +366,7 @@ static int console_output_add_queue( struct object *obj, struct wait_queue_entry
 static struct fd *console_output_get_fd( struct object *obj );
 static struct object *console_output_open_file( struct object *obj, unsigned int access,
                                                 unsigned int sharing, unsigned int options );
+static struct fast_sync *console_output_get_fast_sync( struct object *obj );
 static void console_output_destroy( struct object *obj );
 
 static const struct object_ops console_output_ops =
@@ -377,6 +389,7 @@ static const struct object_ops console_output_ops =
     default_unlink_name,              /* unlink_name */
     console_output_open_file,         /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    console_output_get_fast_sync,     /* get_fast_sync */
     no_close_handle,                  /* close_handle */
     console_output_destroy            /* destroy */
 };
@@ -434,6 +447,7 @@ static const struct object_ops console_connection_ops =
     default_unlink_name,              /* unlink_name */
     console_connection_open_file,     /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_get_fast_sync,                 /* get_fast_sync */
     console_connection_close_handle,  /* close_handle */
     console_connection_destroy        /* destroy */
 };
@@ -516,6 +530,7 @@ static struct object *create_console(void)
     console->server        = NULL;
     console->fd            = NULL;
     console->last_id       = 0;
+    console->fast_sync     = NULL;
     init_async_queue( &console->ioctl_q );
     init_async_queue( &console->read_q );
 
@@ -555,6 +570,7 @@ static int queue_host_ioctl( struct console_server *server, unsigned int code, u
     }
     list_add_tail( &server->queue, &ioctl->entry );
     wake_up( &server->obj, 0 );
+    fast_set_event( server->fast_sync );
     if (async) set_error( STATUS_PENDING );
     return 1;
 }
@@ -587,6 +603,7 @@ static void disconnect_console_server( struct console_server *server )
         server->console->server = NULL;
         server->console = NULL;
         wake_up( &server->obj, 0 );
+        fast_set_event( server->fast_sync );
     }
 }
 
@@ -718,6 +735,8 @@ static void console_destroy( struct object *obj )
     free_async_queue( &console->read_q );
     if (console->fd)
         release_object( console->fd );
+
+    if (console->fast_sync) release_object( console->fast_sync );
 }
 
 static struct object *create_console_connection( struct console *console )
@@ -765,6 +784,16 @@ static struct object *console_open_file( struct object *obj, unsigned int access
     return grab_object( obj );
 }
 
+static struct fast_sync *console_get_fast_sync( struct object *obj )
+{
+    struct console *console = (struct console *)obj;
+
+    if (!console->fast_sync)
+        console->fast_sync = fast_create_event( FAST_SYNC_SERVER, 1, console->signaled );
+    if (console->fast_sync) grab_object( console->fast_sync );
+    return console->fast_sync;
+}
+
 static void screen_buffer_dump( struct object *obj, int verbose )
 {
     struct screen_buffer *screen_buffer = (struct screen_buffer *)obj;
@@ -814,6 +843,17 @@ static struct fd *screen_buffer_get_fd( struct object *obj )
     return NULL;
 }
 
+static struct fast_sync *screen_buffer_get_fast_sync( struct object *obj )
+{
+    struct screen_buffer *screen_buffer = (struct screen_buffer *)obj;
+    if (!screen_buffer->input)
+    {
+        set_error( STATUS_ACCESS_DENIED );
+        return NULL;
+    }
+    return console_get_fast_sync( &screen_buffer->input->obj );
+}
+
 static void console_server_dump( struct object *obj, int verbose )
 {
     assert( obj->ops == &console_server_ops );
@@ -826,6 +866,7 @@ static void console_server_destroy( struct object *obj )
     assert( obj->ops == &console_server_ops );
     disconnect_console_server( server );
     if (server->fd) release_object( server->fd );
+    if (server->fast_sync) release_object( server->fast_sync );
 }
 
 static struct object *console_server_lookup_name( struct object *obj, struct unicode_str *name,
@@ -880,6 +921,17 @@ static struct object *console_server_open_file( struct object *obj, unsigned int
     return grab_object( obj );
 }
 
+static struct fast_sync *console_server_get_fast_sync( struct object *obj )
+{
+    struct console_server *server = (struct console_server *)obj;
+    int signaled = !server->console || !list_empty( &server->queue );
+
+    if (!server->fast_sync)
+        server->fast_sync = fast_create_event( FAST_SYNC_SERVER, 1, signaled );
+    if (server->fast_sync) grab_object( server->fast_sync );
+    return server->fast_sync;
+}
+
 static struct object *create_console_server( void )
 {
     struct console_server *server;
@@ -890,6 +942,7 @@ static struct object *create_console_server( void )
     server->term_fd = -1;
     list_init( &server->queue );
     list_init( &server->read_queue );
+    server->fast_sync = NULL;
     server->fd = alloc_pseudo_fd( &console_server_fd_ops, &server->obj, FILE_SYNCHRONOUS_IO_NONALERT );
     if (!server->fd)
     {
@@ -1339,6 +1392,16 @@ static struct object *console_input_open_file( struct object *obj, unsigned int
     return grab_object( obj );
 }
 
+static struct fast_sync *console_input_get_fast_sync( struct object *obj )
+{
+    if (!current->process->console)
+    {
+        set_error( STATUS_ACCESS_DENIED );
+        return NULL;
+    }
+    return console_get_fast_sync( &current->process->console->obj );
+}
+
 static void console_input_destroy( struct object *obj )
 {
     struct console_input *console_input = (struct console_input *)obj;
@@ -1411,6 +1474,16 @@ static struct object *console_output_open_file( struct object *obj, unsigned int
     return grab_object( obj );
 }
 
+static struct fast_sync *console_output_get_fast_sync( struct object *obj )
+{
+    if (!current->process->console || !current->process->console->active)
+    {
+        set_error( STATUS_ACCESS_DENIED );
+        return NULL;
+    }
+    return console_get_fast_sync( &current->process->console->obj );
+}
+
 static void console_output_destroy( struct object *obj )
 {
     struct console_output *console_output = (struct console_output *)obj;
@@ -1468,11 +1541,16 @@ DECL_HANDLER(get_next_console_request)
 
     if (!server->console->renderer) server->console->renderer = current;
 
-    if (!req->signal) server->console->signaled = 0;
+    if (!req->signal)
+    {
+        server->console->signaled = 0;
+        fast_reset_event( server->console->fast_sync );
+    }
     else if (!server->console->signaled)
     {
         server->console->signaled = 1;
         wake_up( &server->console->obj, 0 );
+        fast_set_event( server->console->fast_sync );
     }
 
     if (req->read)
@@ -1494,6 +1572,8 @@ DECL_HANDLER(get_next_console_request)
         /* set result of previous ioctl */
         ioctl = LIST_ENTRY( list_head( &server->queue ), struct console_host_ioctl, entry );
         list_remove( &ioctl->entry );
+        if (list_empty( &server->queue ))
+            fast_reset_event( server->fast_sync );
     }
 
     if (ioctl)
@@ -1593,5 +1673,8 @@ DECL_HANDLER(get_next_console_request)
         set_error( STATUS_PENDING );
     }
 
+    if (list_empty( &server->queue ))
+        fast_reset_event( server->fast_sync );
+
     release_object( server );
 }
diff --git a/server/debugger.c b/server/debugger.c
index 9b814469b19..5e44579e0a7 100644
--- a/server/debugger.c
+++ b/server/debugger.c
@@ -72,6 +72,7 @@ struct debug_obj
     struct object        obj;         /* object header */
     struct list          event_queue; /* pending events queue */
     unsigned int         flags;       /* debug flags */
+    struct fast_sync    *fast_sync;   /* fast synchronization object */
 };
 
 
@@ -99,12 +100,14 @@ static const struct object_ops debug_event_ops =
     NULL,                          /* unlink_name */
     no_open_file,                  /* open_file */
     no_kernel_obj_list,            /* get_kernel_obj_list */
+    no_get_fast_sync,              /* get_fast_sync */
     no_close_handle,               /* close_handle */
     debug_event_destroy            /* destroy */
 };
 
 static void debug_obj_dump( struct object *obj, int verbose );
 static int debug_obj_signaled( struct object *obj, struct wait_queue_entry *entry );
+static struct fast_sync *debug_obj_get_fast_sync( struct object *obj );
 static void debug_obj_destroy( struct object *obj );
 
 static const struct object_ops debug_obj_ops =
@@ -127,6 +130,7 @@ static const struct object_ops debug_obj_ops =
     default_unlink_name,           /* unlink_name */
     no_open_file,                  /* open_file */
     no_kernel_obj_list,            /* get_kernel_obj_list */
+    debug_obj_get_fast_sync,       /* get_fast_sync */
     no_close_handle,               /* close_handle */
     debug_obj_destroy              /* destroy */
 };
@@ -254,6 +258,7 @@ static void link_event( struct debug_obj *debug_obj, struct debug_event *event )
         /* grab reference since debugger could be killed while trying to wake up */
         grab_object( debug_obj );
         wake_up( &debug_obj->obj, 0 );
+        fast_set_event( debug_obj->fast_sync );
         release_object( debug_obj );
     }
 }
@@ -266,6 +271,7 @@ static void resume_event( struct debug_obj *debug_obj, struct debug_event *event
     {
         grab_object( debug_obj );
         wake_up( &debug_obj->obj, 0 );
+        fast_set_event( debug_obj->fast_sync );
         release_object( debug_obj );
     }
 }
@@ -331,6 +337,17 @@ static int debug_obj_signaled( struct object *obj, struct wait_queue_entry *entr
     return find_event_to_send( debug_obj ) != NULL;
 }
 
+static struct fast_sync *debug_obj_get_fast_sync( struct object *obj )
+{
+    struct debug_obj *debug_obj = (struct debug_obj *)obj;
+    int signaled = find_event_to_send( debug_obj ) != NULL;
+
+    if (!debug_obj->fast_sync)
+        debug_obj->fast_sync = fast_create_event( FAST_SYNC_SERVER, 1, signaled );
+    if (debug_obj->fast_sync) grab_object( debug_obj->fast_sync );
+    return debug_obj->fast_sync;
+}
+
 static void debug_obj_destroy( struct object *obj )
 {
     struct list *ptr;
@@ -343,6 +360,8 @@ static void debug_obj_destroy( struct object *obj )
     /* free all pending events */
     while ((ptr = list_head( &debug_obj->event_queue )))
         unlink_event( debug_obj, LIST_ENTRY( ptr, struct debug_event, entry ));
+
+    if (debug_obj->fast_sync) release_object( debug_obj->fast_sync );
 }
 
 struct debug_obj *get_debug_obj( struct process *process, obj_handle_t handle, unsigned int access )
@@ -362,6 +381,7 @@ static struct debug_obj *create_debug_obj( struct object *root, const struct uni
         {
             debug_obj->flags = flags;
             list_init( &debug_obj->event_queue );
+            debug_obj->fast_sync = NULL;
         }
     }
     return debug_obj;
@@ -570,6 +590,9 @@ DECL_HANDLER(wait_debug_event)
         reply->tid = get_thread_id( event->sender );
         alloc_event_handles( event, current->process );
         set_reply_data( &event->data, min( get_reply_max_size(), sizeof(event->data) ));
+
+        if (!find_event_to_send( debug_obj ))
+            fast_reset_event( debug_obj->fast_sync );
     }
     else
     {
diff --git a/server/device.c b/server/device.c
index 6400751e339..b3f4329d11b 100644
--- a/server/device.c
+++ b/server/device.c
@@ -80,6 +80,7 @@ static const struct object_ops irp_call_ops =
     NULL,                             /* unlink_name */
     no_open_file,                     /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_get_fast_sync,                 /* get_fast_sync */
     no_close_handle,                  /* close_handle */
     irp_call_destroy                  /* destroy */
 };
@@ -94,10 +95,12 @@ struct device_manager
     struct list            requests;       /* list of pending irps across all devices */
     struct irp_call       *current_call;   /* call currently executed on client side */
     struct wine_rb_tree    kernel_objects; /* map of objects that have client side pointer associated */
+    struct fast_sync      *fast_sync;      /* fast synchronization object */
 };
 
 static void device_manager_dump( struct object *obj, int verbose );
 static int device_manager_signaled( struct object *obj, struct wait_queue_entry *entry );
+static struct fast_sync *device_manager_get_fast_sync( struct object *obj );
 static void device_manager_destroy( struct object *obj );
 
 static const struct object_ops device_manager_ops =
@@ -120,6 +123,7 @@ static const struct object_ops device_manager_ops =
     NULL,                             /* unlink_name */
     no_open_file,                     /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    device_manager_get_fast_sync,     /* get_fast_sync */
     no_close_handle,                  /* close_handle */
     device_manager_destroy            /* destroy */
 };
@@ -177,6 +181,7 @@ static const struct object_ops device_ops =
     default_unlink_name,              /* unlink_name */
     device_open_file,                 /* open_file */
     device_get_kernel_obj_list,       /* get_kernel_obj_list */
+    no_get_fast_sync,                 /* get_fast_sync */
     no_close_handle,                  /* close_handle */
     device_destroy                    /* destroy */
 };
@@ -229,6 +234,7 @@ static const struct object_ops device_file_ops =
     NULL,                             /* unlink_name */
     no_open_file,                     /* open_file */
     device_file_get_kernel_obj_list,  /* get_kernel_obj_list */
+    default_fd_get_fast_sync,         /* get_fast_sync */
     device_file_close_handle,         /* close_handle */
     device_file_destroy               /* destroy */
 };
@@ -439,7 +445,12 @@ static void add_irp_to_queue( struct device_manager *manager, struct irp_call *i
     irp->thread = thread ? (struct thread *)grab_object( thread ) : NULL;
     if (irp->file) list_add_tail( &irp->file->requests, &irp->dev_entry );
     list_add_tail( &manager->requests, &irp->mgr_entry );
-    if (list_head( &manager->requests ) == &irp->mgr_entry) wake_up( &manager->obj, 0 );  /* first one */
+    if (list_head( &manager->requests ) == &irp->mgr_entry)
+    {
+        /* first one */
+        wake_up( &manager->obj, 0 );
+        fast_set_event( manager->fast_sync );
+    }
 }
 
 static struct object *device_open_file( struct object *obj, unsigned int access,
@@ -775,6 +786,9 @@ static void delete_file( struct device_file *file )
         set_irp_result( irp, STATUS_FILE_DELETED, NULL, 0, 0 );
     }
 
+    if (list_empty( &file->device->manager->requests ))
+        fast_reset_event( file->device->manager->fast_sync );
+
     release_object( file );
 }
 
@@ -806,6 +820,16 @@ static int device_manager_signaled( struct object *obj, struct wait_queue_entry
     return !list_empty( &manager->requests );
 }
 
+static struct fast_sync *device_manager_get_fast_sync( struct object *obj )
+{
+    struct device_manager *manager = (struct device_manager *)obj;
+
+    if (!manager->fast_sync)
+        manager->fast_sync = fast_create_event( FAST_SYNC_SERVER, 1, !list_empty( &manager->requests ) );
+    if (manager->fast_sync) grab_object( manager->fast_sync );
+    return manager->fast_sync;
+}
+
 static void device_manager_destroy( struct object *obj )
 {
     struct device_manager *manager = (struct device_manager *)obj;
@@ -840,6 +864,8 @@ static void device_manager_destroy( struct object *obj )
         assert( !irp->file && !irp->async );
         release_object( irp );
     }
+
+    if (manager->fast_sync) release_object( manager->fast_sync );
 }
 
 static struct device_manager *create_device_manager(void)
@@ -849,6 +875,7 @@ static struct device_manager *create_device_manager(void)
     if ((manager = alloc_object( &device_manager_ops )))
     {
         manager->current_call = NULL;
+        manager->fast_sync = NULL;
         list_init( &manager->devices );
         list_init( &manager->requests );
         wine_rb_init( &manager->kernel_objects, compare_kernel_object );
@@ -1014,6 +1041,10 @@ DECL_HANDLER(get_next_device_request)
                 iosb->in_size = 0;
                 list_remove( &irp->mgr_entry );
                 list_init( &irp->mgr_entry );
+
+                if (list_empty( &manager->requests ))
+                    fast_reset_event( manager->fast_sync );
+
                 /* we already own the object if it's only on manager queue */
                 if (irp->file) grab_object( irp );
                 manager->current_call = irp;
diff --git a/server/directory.c b/server/directory.c
index 30d69459984..4a0ec8867f8 100644
--- a/server/directory.c
+++ b/server/directory.c
@@ -82,6 +82,7 @@ static const struct object_ops object_type_ops =
     default_unlink_name,          /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_get_fast_sync,             /* get_fast_sync */
     no_close_handle,              /* close_handle */
     no_destroy                    /* destroy */
 };
@@ -132,6 +133,7 @@ static const struct object_ops directory_ops =
     default_unlink_name,          /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_get_fast_sync,             /* get_fast_sync */
     no_close_handle,              /* close_handle */
     directory_destroy             /* destroy */
 };
diff --git a/server/event.c b/server/event.c
index ccdd465dd5b..857bc1ab23b 100644
--- a/server/event.c
+++ b/server/event.c
@@ -56,6 +56,7 @@ struct event
     struct list    kernel_object;   /* list of kernel object pointers */
     int            manual_reset;    /* is it a manual reset event? */
     int            signaled;        /* event has been signaled */
+    struct fast_sync *fast_sync;    /* fast synchronization object */
 };
 
 static void event_dump( struct object *obj, int verbose );
@@ -63,6 +64,8 @@ static int event_signaled( struct object *obj, struct wait_queue_entry *entry );
 static void event_satisfied( struct object *obj, struct wait_queue_entry *entry );
 static int event_signal( struct object *obj, unsigned int access);
 static struct list *event_get_kernel_obj_list( struct object *obj );
+static struct fast_sync *event_get_fast_sync( struct object *obj );
+static void event_destroy( struct object *obj );
 
 static const struct object_ops event_ops =
 {
@@ -84,8 +87,9 @@ static const struct object_ops event_ops =
     default_unlink_name,       /* unlink_name */
     no_open_file,              /* open_file */
     event_get_kernel_obj_list, /* get_kernel_obj_list */
+    event_get_fast_sync,       /* get_fast_sync */
     no_close_handle,           /* close_handle */
-    no_destroy                 /* destroy */
+    event_destroy              /* destroy */
 };
 
 
@@ -106,10 +110,13 @@ struct type_descr keyed_event_type =
 struct keyed_event
 {
     struct object  obj;             /* object header */
+    struct fast_sync *fast_sync;    /* fast synchronization object */
 };
 
 static void keyed_event_dump( struct object *obj, int verbose );
 static int keyed_event_signaled( struct object *obj, struct wait_queue_entry *entry );
+static struct fast_sync *keyed_event_get_fast_sync( struct object *obj );
+static void keyed_event_destroy( struct object *obj );
 
 static const struct object_ops keyed_event_ops =
 {
@@ -131,8 +138,9 @@ static const struct object_ops keyed_event_ops =
     default_unlink_name,         /* unlink_name */
     no_open_file,                /* open_file */
     no_kernel_obj_list,          /* get_kernel_obj_list */
+    keyed_event_get_fast_sync,   /* get_fast_sync */
     no_close_handle,             /* close_handle */
-    no_destroy                   /* destroy */
+    keyed_event_destroy          /* destroy */
 };
 
 
@@ -150,6 +158,7 @@ struct event *create_event( struct object *root, const struct unicode_str *name,
             list_init( &event->kernel_object );
             event->manual_reset = manual_reset;
             event->signaled     = initial_state;
+            event->fast_sync    = NULL;
         }
     }
     return event;
@@ -173,11 +182,13 @@ void set_event( struct event *event )
     event->signaled = 1;
     /* wake up all waiters if manual reset, a single one otherwise */
     wake_up( &event->obj, !event->manual_reset );
+    fast_set_event( event->fast_sync );
 }
 
 void reset_event( struct event *event )
 {
     event->signaled = 0;
+    fast_reset_event( event->fast_sync );
 }
 
 static void event_dump( struct object *obj, int verbose )
@@ -223,6 +234,23 @@ static struct list *event_get_kernel_obj_list( struct object *obj )
     return &event->kernel_object;
 }
 
+static struct fast_sync *event_get_fast_sync( struct object *obj )
+{
+    struct event *event = (struct event *)obj;
+
+    if (!event->fast_sync)
+        event->fast_sync = fast_create_event( FAST_SYNC_EVENT, event->manual_reset, event->signaled );
+    if (event->fast_sync) grab_object( event->fast_sync );
+    return event->fast_sync;
+}
+
+static void event_destroy( struct object *obj )
+{
+    struct event *event = (struct event *)obj;
+
+    if (event->fast_sync) release_object( event->fast_sync );
+}
+
 struct keyed_event *create_keyed_event( struct object *root, const struct unicode_str *name,
                                         unsigned int attr, const struct security_descriptor *sd )
 {
@@ -233,6 +261,7 @@ struct keyed_event *create_keyed_event( struct object *root, const struct unicod
         if (get_error() != STATUS_OBJECT_NAME_EXISTS)
         {
             /* initialize it if it didn't already exist */
+            event->fast_sync = NULL;
         }
     }
     return event;
@@ -276,6 +305,23 @@ static int keyed_event_signaled( struct object *obj, struct wait_queue_entry *en
     return 0;
 }
 
+static struct fast_sync *keyed_event_get_fast_sync( struct object *obj )
+{
+    struct keyed_event *event = (struct keyed_event *)obj;
+
+    if (!event->fast_sync)
+        event->fast_sync = fast_create_event( FAST_SYNC_SERVER, 1, 1 );
+    if (event->fast_sync) grab_object( event->fast_sync );
+    return event->fast_sync;
+}
+
+static void keyed_event_destroy( struct object *obj )
+{
+    struct keyed_event *event = (struct keyed_event *)obj;
+
+    if (event->fast_sync) release_object( event->fast_sync );
+}
+
 /* create an event */
 DECL_HANDLER(create_event)
 {
diff --git a/server/fast_sync.c b/server/fast_sync.c
new file mode 100644
index 00000000000..f0dae236ca3
--- /dev/null
+++ b/server/fast_sync.c
@@ -0,0 +1,427 @@
+/*
+ * Fast synchronization primitives
+ *
+ * Copyright (C) 2021 Zebediah Figura for CodeWeavers
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#include "config.h"
+
+#include <assert.h>
+#include <fcntl.h>
+#ifdef HAVE_LINUX_WINESYNC_H
+# include <linux/winesync.h>
+#endif
+#include <stdio.h>
+#ifdef HAVE_SYS_IOCTL_H
+# include <sys/ioctl.h>
+#endif
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "ntstatus.h"
+#define WIN32_NO_STATUS
+#include "winternl.h"
+
+#include "file.h"
+#include "handle.h"
+#include "request.h"
+#include "thread.h"
+
+#ifdef HAVE_LINUX_WINESYNC_H
+
+struct fast_sync_device
+{
+    struct object obj;      /* object header */
+    struct fd *fd;          /* fd for unix fd */
+};
+
+static struct fast_sync_device *fast_sync_device_object;
+
+static void fast_sync_device_dump( struct object *obj, int verbose );
+static struct fd *fast_sync_device_get_fd( struct object *obj );
+static void fast_sync_device_destroy( struct object *obj );
+static enum server_fd_type fast_sync_device_get_fd_type( struct fd *fd );
+
+static const struct object_ops fast_sync_device_ops =
+{
+    sizeof(struct fast_sync_device),    /* size */
+    &no_type,                           /* type */
+    fast_sync_device_dump,              /* dump */
+    no_add_queue,                       /* add_queue */
+    NULL,                               /* remove_queue */
+    NULL,                               /* signaled */
+    NULL,                               /* satisfied */
+    no_signal,                          /* signal */
+    fast_sync_device_get_fd,            /* get_fd */
+    default_map_access,                 /* map_access */
+    default_get_sd,                     /* get_sd */
+    default_set_sd,                     /* set_sd */
+    no_get_full_name,                   /* get_full_name */
+    no_lookup_name,                     /* lookup_name */
+    no_link_name,                       /* link_name */
+    NULL,                               /* unlink_name */
+    no_open_file,                       /* open_file */
+    no_kernel_obj_list,                 /* get_kernel_obj_list */
+    no_get_fast_sync,                   /* get_fast_sync */
+    no_close_handle,                    /* close_handle */
+    fast_sync_device_destroy            /* destroy */
+};
+
+static const struct fd_ops fast_sync_device_fd_ops =
+{
+    default_fd_get_poll_events,     /* get_poll_events */
+    default_poll_event,             /* poll_event */
+    fast_sync_device_get_fd_type,   /* get_fd_type */
+    no_fd_read,                     /* read */
+    no_fd_write,                    /* write */
+    no_fd_flush,                    /* flush */
+    no_fd_get_file_info,            /* get_file_info */
+    no_fd_get_volume_info,          /* get_volume_info */
+    no_fd_ioctl,                    /* ioctl */
+    no_fd_queue_async,              /* queue_async */
+    default_fd_reselect_async       /* reselect_async */
+};
+
+static void fast_sync_device_dump( struct object *obj, int verbose )
+{
+    struct fast_sync_device *device = (struct fast_sync_device *)obj;
+    assert( obj->ops == &fast_sync_device_ops );
+    fprintf( stderr, "Fast synchronization device fd=%p\n", device->fd );
+}
+
+static struct fd *fast_sync_device_get_fd( struct object *obj )
+{
+    struct fast_sync_device *device = (struct fast_sync_device *)obj;
+    return (struct fd *)grab_object( device->fd );
+}
+
+static void fast_sync_device_destroy( struct object *obj )
+{
+    struct fast_sync_device *device = (struct fast_sync_device *)obj;
+    assert( obj->ops == &fast_sync_device_ops );
+    if (device->fd) release_object( device->fd );
+    fast_sync_device_object = NULL;
+}
+
+static enum server_fd_type fast_sync_device_get_fd_type( struct fd *fd )
+{
+    return FD_TYPE_FILE;
+}
+
+static struct fast_sync_device *get_fast_sync_device(void)
+{
+    struct fast_sync_device *device;
+    int unix_fd;
+
+    if (getenv( "WINE_DISABLE_FAST_SYNC" ) && atoi( getenv( "WINE_DISABLE_FAST_SYNC" ) ))
+    {
+        set_error( STATUS_NOT_IMPLEMENTED );
+        return NULL;
+    }
+
+    if (fast_sync_device_object)
+        return (struct fast_sync_device *)grab_object( fast_sync_device_object );
+
+    unix_fd = open( "/dev/winesync", O_CLOEXEC | O_RDONLY );
+    if (unix_fd == -1)
+    {
+        file_set_error();
+        return NULL;
+    }
+
+    if (!(device = alloc_object( &fast_sync_device_ops )))
+    {
+        close( unix_fd );
+        set_error( STATUS_NO_MEMORY );
+        return NULL;
+    }
+
+    if (!(device->fd = create_anonymous_fd( &fast_sync_device_fd_ops, unix_fd, &device->obj, 0 )))
+    {
+        release_object( device );
+        set_error( STATUS_NO_MEMORY );
+        return NULL;
+    }
+
+    fast_sync_device_object = device;
+    return device;
+}
+
+struct fast_sync
+{
+    struct object obj;
+    struct fast_sync_device *device;
+    enum fast_sync_type type;
+    unsigned int linux_obj;
+};
+
+static void fast_sync_dump( struct object *obj, int verbose );
+static void fast_sync_destroy( struct object *obj );
+
+static const struct object_ops fast_sync_ops =
+{
+    sizeof(struct fast_sync),   /* size */
+    &no_type,                   /* type */
+    fast_sync_dump,             /* dump */
+    no_add_queue,               /* add_queue */
+    NULL,                       /* remove_queue */
+    NULL,                       /* signaled */
+    NULL,                       /* satisfied */
+    no_signal,                  /* signal */
+    no_get_fd,                  /* get_fd */
+    default_map_access,         /* map_access */
+    default_get_sd,             /* get_sd */
+    default_set_sd,             /* set_sd */
+    no_get_full_name,           /* get_full_name */
+    no_lookup_name,             /* lookup_name */
+    no_link_name,               /* link_name */
+    NULL,                       /* unlink_name */
+    no_open_file,               /* open_file */
+    no_kernel_obj_list,         /* get_kernel_obj_list */
+    no_get_fast_sync,           /* get_fast_sync */
+    no_close_handle,            /* close_handle */
+    fast_sync_destroy           /* destroy */
+};
+
+static void fast_sync_dump( struct object *obj, int verbose )
+{
+    struct fast_sync *fast_sync = (struct fast_sync *)obj;
+    assert( obj->ops == &fast_sync_ops );
+    fprintf( stderr, "Fast synchronization object type=%u linux_obj=%u\n",
+             fast_sync->type, fast_sync->linux_obj );
+}
+
+static void fast_sync_destroy( struct object *obj )
+{
+    struct fast_sync *fast_sync = (struct fast_sync *)obj;
+
+    ioctl( get_unix_fd( fast_sync->device->fd ), WINESYNC_IOC_DELETE, &fast_sync->linux_obj );
+    release_object( fast_sync->device );
+}
+
+struct fast_sync *fast_create_event( enum fast_sync_type type, int manual_reset, int signaled )
+{
+    struct winesync_sem_args args = {0};
+    struct fast_sync_device *device;
+    struct fast_sync *fast_sync;
+
+    if (!(device = get_fast_sync_device())) return NULL;
+
+    args.count = signaled;
+    args.max = 1;
+    if (!manual_reset)
+        args.flags |= WINESYNC_SEM_GETONWAIT;
+    if (ioctl( get_unix_fd( device->fd ), WINESYNC_IOC_CREATE_SEM, &args ) < 0)
+    {
+        file_set_error();
+        release_object( device );
+        return NULL;
+    }
+
+    if (!(fast_sync = alloc_object( &fast_sync_ops ))) return NULL;
+
+    /* transfer our device reference to the fast sync object */
+    fast_sync->device = device;
+    fast_sync->type = type;
+    fast_sync->linux_obj = args.sem;
+
+    return fast_sync;
+}
+
+struct fast_sync *fast_create_semaphore( unsigned int count, unsigned int max )
+{
+    struct winesync_sem_args args = {0};
+    struct fast_sync_device *device;
+    struct fast_sync *fast_sync;
+
+    if (!(device = get_fast_sync_device())) return NULL;
+
+    args.count = count;
+    args.max = max;
+    args.flags = WINESYNC_SEM_GETONWAIT;
+    if (ioctl( get_unix_fd( device->fd ), WINESYNC_IOC_CREATE_SEM, &args ) < 0)
+    {
+        file_set_error();
+        release_object( device );
+        return NULL;
+    }
+
+    if (!(fast_sync = alloc_object( &fast_sync_ops ))) return NULL;
+
+    /* transfer our device reference to the fast sync object */
+    fast_sync->device = device;
+    fast_sync->type = FAST_SYNC_SEMAPHORE;
+    fast_sync->linux_obj = args.sem;
+
+    return fast_sync;
+}
+
+struct fast_sync *fast_create_mutex( thread_id_t owner, unsigned int count )
+{
+    struct winesync_mutex_args args = {0};
+    struct fast_sync_device *device;
+    struct fast_sync *fast_sync;
+
+    if (!(device = get_fast_sync_device())) return NULL;
+
+    args.owner = owner;
+    args.count = count;
+    if (ioctl( get_unix_fd( device->fd ), WINESYNC_IOC_CREATE_MUTEX, &args ) < 0)
+    {
+        file_set_error();
+        release_object( device );
+        return NULL;
+    }
+
+    if (!(fast_sync = alloc_object( &fast_sync_ops ))) return NULL;
+
+    /* transfer our device reference to the fast sync object */
+    fast_sync->device = device;
+    fast_sync->type = FAST_SYNC_MUTEX;
+    fast_sync->linux_obj = args.mutex;
+
+    return fast_sync;
+}
+
+void fast_set_event( struct fast_sync *fast_sync )
+{
+    struct winesync_sem_args args = {0};
+
+    if (!fast_sync) return;
+
+    if (debug_level) fprintf( stderr, "fast_set_event %u\n", fast_sync->linux_obj );
+
+    args.sem = fast_sync->linux_obj;
+    args.count = 1;
+    ioctl( get_unix_fd( fast_sync->device->fd ), WINESYNC_IOC_PUT_SEM, &args );
+}
+
+void fast_reset_event( struct fast_sync *fast_sync )
+{
+    if (!fast_sync) return;
+
+    if (debug_level) fprintf( stderr, "fast_reset_event %u\n", fast_sync->linux_obj );
+
+    ioctl( get_unix_fd( fast_sync->device->fd ), WINESYNC_IOC_GET_SEM, &fast_sync->linux_obj );
+}
+
+void fast_abandon_mutexes( thread_id_t tid )
+{
+    struct fast_sync_device *device;
+
+    if (!(device = get_fast_sync_device()))
+    {
+        clear_error();
+        return;
+    }
+
+    ioctl( get_unix_fd( device->fd ), WINESYNC_IOC_KILL_OWNER, &tid );
+    release_object( device );
+}
+
+int fast_user_apc_needs_signal(void)
+{
+    return !!fast_sync_device_object;
+}
+
+#else
+
+static struct fast_sync_device *get_fast_sync_device(void)
+{
+    set_error( STATUS_NOT_IMPLEMENTED );
+    return NULL;
+}
+
+struct fast_sync *fast_create_event( enum fast_sync_type type, int manual_reset, int signaled )
+{
+    set_error( STATUS_NOT_IMPLEMENTED );
+    return NULL;
+}
+
+struct fast_sync *fast_create_semaphore( unsigned int count, unsigned int max )
+{
+    set_error( STATUS_NOT_IMPLEMENTED );
+    return NULL;
+}
+
+struct fast_sync *fast_create_mutex( thread_id_t owner, unsigned int count )
+{
+    set_error( STATUS_NOT_IMPLEMENTED );
+    return NULL;
+}
+
+void fast_set_event( struct fast_sync *fast_sync )
+{
+}
+
+void fast_reset_event( struct fast_sync *obj )
+{
+}
+
+void fast_abandon_mutexes( thread_id_t tid )
+{
+}
+
+int fast_user_apc_needs_signal(void)
+{
+    return 0;
+}
+
+#endif
+
+DECL_HANDLER(get_fast_sync_device)
+{
+#ifdef HAVE_LINUX_WINESYNC_H
+    struct fast_sync_device *device;
+
+    if ((device = get_fast_sync_device()))
+    {
+        reply->handle = alloc_handle( current->process, device, 0, 0 );
+        release_object( device );
+    }
+#else
+    set_error( STATUS_NOT_IMPLEMENTED );
+#endif
+}
+
+DECL_HANDLER(get_fast_sync_obj)
+{
+#ifdef HAVE_LINUX_WINESYNC_H
+    struct object *obj;
+    static int once;
+
+    if (!once++)
+        fprintf( stderr, "wine: using fast synchronization.\n" );
+
+    if ((obj = get_handle_obj( current->process, req->handle, 0, NULL )))
+    {
+        struct fast_sync *fast_sync;
+
+        if ((fast_sync = obj->ops->get_fast_sync( obj )))
+        {
+            reply->handle = alloc_handle( current->process, fast_sync, 0, 0 );
+            reply->obj = fast_sync->linux_obj;
+            reply->type = fast_sync->type;
+            reply->access = get_handle_access( current->process, req->handle );
+            release_object( fast_sync );
+        }
+        release_object( obj );
+    }
+#else
+    set_error( STATUS_NOT_IMPLEMENTED );
+#endif
+}
diff --git a/server/fd.c b/server/fd.c
index bfa2805d82b..2b7ed1b752e 100644
--- a/server/fd.c
+++ b/server/fd.c
@@ -199,6 +199,7 @@ struct fd
     struct completion   *completion;  /* completion object attached to this fd */
     apc_param_t          comp_key;    /* completion key to set in completion events */
     unsigned int         comp_flags;  /* completion flags */
+    struct fast_sync    *fast_sync;   /* fast synchronization object */
 };
 
 static void fd_dump( struct object *obj, int verbose );
@@ -224,6 +225,7 @@ static const struct object_ops fd_ops =
     NULL,                     /* unlink_name */
     no_open_file,             /* open_file */
     no_kernel_obj_list,       /* get_kernel_obj_list */
+    no_get_fast_sync,         /* get_fast_sync */
     no_close_handle,          /* close_handle */
     fd_destroy                /* destroy */
 };
@@ -265,6 +267,7 @@ static const struct object_ops device_ops =
     NULL,                     /* unlink_name */
     no_open_file,             /* open_file */
     no_kernel_obj_list,       /* get_kernel_obj_list */
+    no_get_fast_sync,         /* get_fast_sync */
     no_close_handle,          /* close_handle */
     device_destroy            /* destroy */
 };
@@ -305,6 +308,7 @@ static const struct object_ops inode_ops =
     NULL,                     /* unlink_name */
     no_open_file,             /* open_file */
     no_kernel_obj_list,       /* get_kernel_obj_list */
+    no_get_fast_sync,         /* get_fast_sync */
     no_close_handle,          /* close_handle */
     inode_destroy             /* destroy */
 };
@@ -347,6 +351,7 @@ static const struct object_ops file_lock_ops =
     NULL,                       /* unlink_name */
     no_open_file,               /* open_file */
     no_kernel_obj_list,         /* get_kernel_obj_list */
+    no_get_fast_sync,           /* get_fast_sync */
     no_close_handle,            /* close_handle */
     no_destroy                  /* destroy */
 };
@@ -1580,6 +1585,7 @@ static void fd_destroy( struct object *obj )
         if (fd->unix_fd != -1) close( fd->unix_fd );
         free( fd->unix_name );
     }
+    if (fd->fast_sync) release_object( fd->fast_sync );
 }
 
 /* check if the desired access is possible without violating */
@@ -1696,6 +1702,7 @@ static struct fd *alloc_fd_object(void)
     fd->poll_index = -1;
     fd->completion = NULL;
     fd->comp_flags = 0;
+    fd->fast_sync  = NULL;
     init_async_queue( &fd->read_q );
     init_async_queue( &fd->write_q );
     init_async_queue( &fd->wait_q );
@@ -1734,6 +1741,7 @@ struct fd *alloc_pseudo_fd( const struct fd_ops *fd_user_ops, struct object *use
     fd->poll_index = -1;
     fd->completion = NULL;
     fd->comp_flags = 0;
+    fd->fast_sync  = NULL;
     fd->no_fd_status = STATUS_BAD_DEVICE_TYPE;
     init_async_queue( &fd->read_q );
     init_async_queue( &fd->write_q );
@@ -2118,7 +2126,15 @@ void set_fd_signaled( struct fd *fd, int signaled )
 {
     if (fd->comp_flags & FILE_SKIP_SET_EVENT_ON_HANDLE) return;
     fd->signaled = signaled;
-    if (signaled) wake_up( fd->user, 0 );
+    if (signaled)
+    {
+        wake_up( fd->user, 0 );
+        fast_set_event( fd->fast_sync );
+    }
+    else
+    {
+        fast_reset_event( fd->fast_sync );
+    }
 }
 
 /* check if events are pending and if yes return which one(s) */
@@ -2144,6 +2160,19 @@ int default_fd_signaled( struct object *obj, struct wait_queue_entry *entry )
     return ret;
 }
 
+struct fast_sync *default_fd_get_fast_sync( struct object *obj )
+{
+    struct fd *fd = get_obj_fd( obj );
+    struct fast_sync *ret;
+
+    if (!fd->fast_sync)
+        fd->fast_sync = fast_create_event( FAST_SYNC_SERVER, 1, fd->signaled );
+    ret = fd->fast_sync;
+    release_object( fd );
+    if (ret) grab_object( ret );
+    return ret;
+}
+
 int default_fd_get_poll_events( struct fd *fd )
 {
     int events = 0;
diff --git a/server/file.c b/server/file.c
index aff4d9e09e1..8c684141fa6 100644
--- a/server/file.c
+++ b/server/file.c
@@ -109,6 +109,7 @@ static const struct object_ops file_ops =
     NULL,                         /* unlink_name */
     file_open_file,               /* open_file */
     file_get_kernel_obj_list,     /* get_kernel_obj_list */
+    default_fd_get_fast_sync,     /* get_fast_sync */
     no_close_handle,              /* close_handle */
     file_destroy                  /* destroy */
 };
diff --git a/server/file.h b/server/file.h
index b8bc7645b19..0989bae1d87 100644
--- a/server/file.h
+++ b/server/file.h
@@ -104,6 +104,7 @@ extern char *dup_fd_name( struct fd *root, const char *name );
 extern void get_nt_name( struct fd *fd, struct unicode_str *name );
 
 extern int default_fd_signaled( struct object *obj, struct wait_queue_entry *entry );
+extern struct fast_sync *default_fd_get_fast_sync( struct object *obj );
 extern int default_fd_get_poll_events( struct fd *fd );
 extern void default_poll_event( struct fd *fd, int event );
 extern void fd_queue_async( struct fd *fd, struct async *async, int type );
diff --git a/server/handle.c b/server/handle.c
index d86f0960ccf..6cf388cd1d5 100644
--- a/server/handle.c
+++ b/server/handle.c
@@ -138,6 +138,7 @@ static const struct object_ops handle_table_ops =
     NULL,                            /* unlink_name */
     no_open_file,                    /* open_file */
     no_kernel_obj_list,              /* get_kernel_obj_list */
+    no_get_fast_sync,                /* get_fast_sync */
     no_close_handle,                 /* close_handle */
     handle_table_destroy             /* destroy */
 };
diff --git a/server/hook.c b/server/hook.c
index c048908c295..8d1f7895313 100644
--- a/server/hook.c
+++ b/server/hook.c
@@ -93,6 +93,7 @@ static const struct object_ops hook_table_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_get_fast_sync,             /* get_fast_sync */
     no_close_handle,              /* close_handle */
     hook_table_destroy            /* destroy */
 };
diff --git a/server/mailslot.c b/server/mailslot.c
index d4b2fd1b562..88aee771e5e 100644
--- a/server/mailslot.c
+++ b/server/mailslot.c
@@ -90,6 +90,7 @@ static const struct object_ops mailslot_ops =
     default_unlink_name,       /* unlink_name */
     mailslot_open_file,        /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    default_fd_get_fast_sync,  /* get_fast_sync */
     no_close_handle,           /* close_handle */
     mailslot_destroy           /* destroy */
 };
@@ -148,6 +149,7 @@ static const struct object_ops mail_writer_ops =
     NULL,                       /* unlink_name */
     no_open_file,               /* open_file */
     no_kernel_obj_list,         /* get_kernel_obj_list */
+    no_get_fast_sync,           /* get_fast_sync */
     no_close_handle,            /* close_handle */
     mail_writer_destroy         /* destroy */
 };
@@ -210,6 +212,7 @@ static const struct object_ops mailslot_device_ops =
     default_unlink_name,            /* unlink_name */
     mailslot_device_open_file,      /* open_file */
     no_kernel_obj_list,             /* get_kernel_obj_list */
+    no_get_fast_sync,               /* get_fast_sync */
     no_close_handle,                /* close_handle */
     mailslot_device_destroy         /* destroy */
 };
@@ -240,6 +243,7 @@ static const struct object_ops mailslot_device_file_ops =
     NULL,                                   /* unlink_name */
     no_open_file,                           /* open_file */
     no_kernel_obj_list,                     /* get_kernel_obj_list */
+    default_fd_get_fast_sync,               /* get_fast_sync */
     no_close_handle,                        /* close_handle */
     mailslot_device_file_destroy            /* destroy */
 };
diff --git a/server/mapping.c b/server/mapping.c
index 9cb24a4213f..c03d18254d3 100644
--- a/server/mapping.c
+++ b/server/mapping.c
@@ -80,6 +80,7 @@ static const struct object_ops ranges_ops =
     NULL,                      /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    no_get_fast_sync,          /* get_fast_sync */
     no_close_handle,           /* close_handle */
     ranges_destroy             /* destroy */
 };
@@ -116,6 +117,7 @@ static const struct object_ops shared_map_ops =
     NULL,                      /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    no_get_fast_sync,          /* get_fast_sync */
     no_close_handle,           /* close_handle */
     shared_map_destroy         /* destroy */
 };
@@ -189,6 +191,7 @@ static const struct object_ops mapping_ops =
     default_unlink_name,         /* unlink_name */
     no_open_file,                /* open_file */
     no_kernel_obj_list,          /* get_kernel_obj_list */
+    no_get_fast_sync,            /* get_fast_sync */
     no_close_handle,             /* close_handle */
     mapping_destroy              /* destroy */
 };
diff --git a/server/mutex.c b/server/mutex.c
index 75ff5117d3f..ca5d38da5ea 100644
--- a/server/mutex.c
+++ b/server/mutex.c
@@ -57,6 +57,7 @@ struct mutex
     unsigned int   count;           /* recursion count */
     int            abandoned;       /* has it been abandoned? */
     struct list    entry;           /* entry in owner thread mutex list */
+    struct fast_sync *fast_sync;    /* fast synchronization object */
 };
 
 static void mutex_dump( struct object *obj, int verbose );
@@ -64,6 +65,7 @@ static int mutex_signaled( struct object *obj, struct wait_queue_entry *entry );
 static void mutex_satisfied( struct object *obj, struct wait_queue_entry *entry );
 static void mutex_destroy( struct object *obj );
 static int mutex_signal( struct object *obj, unsigned int access );
+static struct fast_sync *mutex_get_fast_sync( struct object *obj );
 
 static const struct object_ops mutex_ops =
 {
@@ -85,6 +87,7 @@ static const struct object_ops mutex_ops =
     default_unlink_name,       /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    mutex_get_fast_sync,       /* get_fast_sync */
     no_close_handle,           /* close_handle */
     mutex_destroy              /* destroy */
 };
@@ -127,6 +130,7 @@ static struct mutex *create_mutex( struct object *root, const struct unicode_str
             mutex->owner = NULL;
             mutex->abandoned = 0;
             if (owned) do_grab( mutex, current );
+            mutex->fast_sync = NULL;
         }
     }
     return mutex;
@@ -189,14 +193,27 @@ static int mutex_signal( struct object *obj, unsigned int access )
     return 1;
 }
 
+static struct fast_sync *mutex_get_fast_sync( struct object *obj )
+{
+    struct mutex *mutex = (struct mutex *)obj;
+
+    if (!mutex->fast_sync)
+        mutex->fast_sync = fast_create_mutex( mutex->owner ? mutex->owner->id : 0, mutex->count );
+    if (mutex->fast_sync) grab_object( mutex->fast_sync );
+    return mutex->fast_sync;
+}
+
 static void mutex_destroy( struct object *obj )
 {
     struct mutex *mutex = (struct mutex *)obj;
     assert( obj->ops == &mutex_ops );
 
-    if (!mutex->count) return;
-    mutex->count = 0;
-    do_release( mutex );
+    if (mutex->count)
+    {
+        mutex->count = 0;
+        do_release( mutex );
+    }
+    if (mutex->fast_sync) release_object( mutex->fast_sync );
 }
 
 /* create a mutex */
diff --git a/server/named_pipe.c b/server/named_pipe.c
index df8c7e3170c..3bc91bb8350 100644
--- a/server/named_pipe.c
+++ b/server/named_pipe.c
@@ -131,6 +131,7 @@ static const struct object_ops named_pipe_ops =
     default_unlink_name,          /* unlink_name */
     named_pipe_open_file,         /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_get_fast_sync,             /* get_fast_sync */
     no_close_handle,              /* close_handle */
     named_pipe_destroy            /* destroy */
 };
@@ -179,6 +180,7 @@ static const struct object_ops pipe_server_ops =
     NULL,                         /* unlink_name */
     pipe_server_open_file,        /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    default_fd_get_fast_sync,     /* get_fast_sync */
     no_close_handle,              /* close_handle */
     pipe_server_destroy           /* destroy */
 };
@@ -222,6 +224,7 @@ static const struct object_ops pipe_client_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    default_fd_get_fast_sync,     /* get_fast_sync */
     no_close_handle,              /* close_handle */
     pipe_end_destroy              /* destroy */
 };
@@ -268,6 +271,7 @@ static const struct object_ops named_pipe_device_ops =
     default_unlink_name,              /* unlink_name */
     named_pipe_device_open_file,      /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_get_fast_sync,                 /* get_fast_sync */
     no_close_handle,                  /* close_handle */
     named_pipe_device_destroy         /* destroy */
 };
@@ -299,6 +303,7 @@ static const struct object_ops named_pipe_device_file_ops =
     NULL,                                    /* unlink_name */
     no_open_file,                            /* open_file */
     no_kernel_obj_list,                      /* get_kernel_obj_list */
+    default_fd_get_fast_sync,                /* get_fast_sync */
     no_close_handle,                         /* close_handle */
     named_pipe_device_file_destroy           /* destroy */
 };
diff --git a/server/object.c b/server/object.c
index b2779fd61fe..e8d6783537c 100644
--- a/server/object.c
+++ b/server/object.c
@@ -528,6 +528,12 @@ struct fd *no_get_fd( struct object *obj )
     return NULL;
 }
 
+struct fast_sync *no_get_fast_sync( struct object *obj )
+{
+    set_error( STATUS_OBJECT_TYPE_MISMATCH );
+    return NULL;
+}
+
 unsigned int default_map_access( struct object *obj, unsigned int access )
 {
     return map_access( access, &obj->ops->type->mapping );
diff --git a/server/object.h b/server/object.h
index e9d9a87875e..6d77c9bb0c2 100644
--- a/server/object.h
+++ b/server/object.h
@@ -45,6 +45,7 @@ struct async;
 struct async_queue;
 struct winstation;
 struct object_type;
+struct fast_sync;
 
 
 struct unicode_str
@@ -106,6 +107,8 @@ struct object_ops
                                 unsigned int options);
     /* return list of kernel objects */
     struct list *(*get_kernel_obj_list)(struct object *);
+    /* get a client-waitable fast-synchronization handle to this object */
+    struct fast_sync *(*get_fast_sync)(struct object *);
     /* close a handle to this object */
     int (*close_handle)(struct object *,struct process *,obj_handle_t);
     /* destroy on refcount == 0 */
@@ -222,6 +225,18 @@ extern void reset_event( struct event *event );
 
 extern void abandon_mutexes( struct thread *thread );
 
+/* fast-synchronization functions */
+
+extern struct fast_sync *fast_create_event( enum fast_sync_type type, int manual_reset, int signaled );
+extern struct fast_sync *fast_create_semaphore( unsigned int count, unsigned int max );
+extern struct fast_sync *fast_create_mutex( thread_id_t owner, unsigned int count );
+extern void fast_set_event( struct fast_sync *obj );
+extern void fast_reset_event( struct fast_sync *obj );
+extern void fast_abandon_mutexes( thread_id_t tid );
+extern int fast_user_apc_needs_signal(void);
+
+extern struct fast_sync *no_get_fast_sync( struct object *obj );
+
 /* serial functions */
 
 int get_serial_async_timeout(struct object *obj, int type, int count);
diff --git a/server/process.c b/server/process.c
index 5b271b12328..b6ff300eacc 100644
--- a/server/process.c
+++ b/server/process.c
@@ -80,6 +80,7 @@ static unsigned int process_map_access( struct object *obj, unsigned int access
 static struct security_descriptor *process_get_sd( struct object *obj );
 static void process_poll_event( struct fd *fd, int event );
 static struct list *process_get_kernel_obj_list( struct object *obj );
+static struct fast_sync *process_get_fast_sync( struct object *obj );
 static void process_destroy( struct object *obj );
 static void terminate_process( struct process *process, struct thread *skip, int exit_code );
 
@@ -103,6 +104,7 @@ static const struct object_ops process_ops =
     NULL,                        /* unlink_name */
     no_open_file,                /* open_file */
     process_get_kernel_obj_list, /* get_kernel_obj_list */
+    process_get_fast_sync,       /* get_fast_sync */
     no_close_handle,             /* close_handle */
     process_destroy              /* destroy */
 };
@@ -154,6 +156,7 @@ static const struct object_ops startup_info_ops =
     NULL,                          /* unlink_name */
     no_open_file,                  /* open_file */
     no_kernel_obj_list,            /* get_kernel_obj_list */
+    no_get_fast_sync,              /* get_fast_sync */
     no_close_handle,               /* close_handle */
     startup_info_destroy           /* destroy */
 };
@@ -176,6 +179,7 @@ struct type_descr job_type =
 
 static void job_dump( struct object *obj, int verbose );
 static int job_signaled( struct object *obj, struct wait_queue_entry *entry );
+static struct fast_sync *job_get_fast_sync( struct object *obj );
 static int job_close_handle( struct object *obj, struct process *process, obj_handle_t handle );
 static void job_destroy( struct object *obj );
 
@@ -193,6 +197,7 @@ struct job
     struct job *parent;
     struct list parent_job_entry;  /* list entry for parent job */
     struct list child_job_list;    /* list of child jobs */
+    struct fast_sync *fast_sync;   /* fast synchronization object */
 };
 
 static const struct object_ops job_ops =
@@ -215,6 +220,7 @@ static const struct object_ops job_ops =
     default_unlink_name,           /* unlink_name */
     no_open_file,                  /* open_file */
     no_kernel_obj_list,            /* get_kernel_obj_list */
+    job_get_fast_sync,             /* get_fast_sync */
     job_close_handle,              /* close_handle */
     job_destroy                    /* destroy */
 };
@@ -239,6 +245,7 @@ static struct job *create_job_object( struct object *root, const struct unicode_
             job->completion_port = NULL;
             job->completion_key = 0;
             job->parent = NULL;
+            job->fast_sync = NULL;
         }
     }
     return job;
@@ -377,6 +384,17 @@ static void terminate_job( struct job *job, int exit_code )
     job->terminating = 0;
     job->signaled = 1;
     wake_up( &job->obj, 0 );
+    fast_set_event( job->fast_sync );
+}
+
+static struct fast_sync *job_get_fast_sync( struct object *obj )
+{
+    struct job *job = (struct job *)obj;
+
+    if (!job->fast_sync)
+        job->fast_sync = fast_create_event( FAST_SYNC_SERVER, 1, job->signaled );
+    if (job->fast_sync) grab_object( job->fast_sync );
+    return job->fast_sync;
 }
 
 static int job_close_handle( struct object *obj, struct process *process, obj_handle_t handle )
@@ -407,6 +425,8 @@ static void job_destroy( struct object *obj )
         list_remove( &job->parent_job_entry );
         release_object( job->parent );
     }
+
+    if (job->fast_sync) release_object( job->fast_sync );
 }
 
 static void job_dump( struct object *obj, int verbose )
@@ -637,6 +657,7 @@ struct process *create_process( int fd, struct process *parent, unsigned int fla
     process->trace_data      = 0;
     process->rawinput_mouse  = NULL;
     process->rawinput_kbd    = NULL;
+    process->fast_sync       = NULL;
     list_init( &process->kernel_object );
     list_init( &process->thread_list );
     list_init( &process->locks );
@@ -739,6 +760,8 @@ static void process_destroy( struct object *obj )
     if (process->token) release_object( process->token );
     free( process->dir_cache );
     free( process->image );
+
+    if (process->fast_sync) release_object( process->fast_sync );
 }
 
 /* dump a process on stdout for debugging purposes */
@@ -770,6 +793,16 @@ static struct list *process_get_kernel_obj_list( struct object *obj )
     return &process->kernel_object;
 }
 
+static struct fast_sync *process_get_fast_sync( struct object *obj )
+{
+    struct process *process = (struct process *)obj;
+
+    if (!process->fast_sync)
+        process->fast_sync = fast_create_event( FAST_SYNC_SERVER, 1, !process->running_threads );
+    if (process->fast_sync) grab_object( process->fast_sync );
+    return process->fast_sync;
+}
+
 static struct security_descriptor *process_get_sd( struct object *obj )
 {
     static struct security_descriptor *process_default_sd;
@@ -950,6 +983,7 @@ static void process_killed( struct process *process )
     release_job_process( process );
     start_sigkill_timer( process );
     wake_up( &process->obj, 0 );
+    fast_set_event( process->fast_sync );
 }
 
 /* add a thread to a process running threads list */
diff --git a/server/process.h b/server/process.h
index 0e1a83859d9..7c25f998735 100644
--- a/server/process.h
+++ b/server/process.h
@@ -87,6 +87,7 @@ struct process
     const struct rawinput_device *rawinput_mouse; /* rawinput mouse device, if any */
     const struct rawinput_device *rawinput_kbd;   /* rawinput keyboard device, if any */
     struct list          kernel_object;   /* list of kernel object pointers */
+    struct fast_sync    *fast_sync;       /* fast synchronization object */
 };
 
 /* process functions */
diff --git a/server/protocol.def b/server/protocol.def
index 30624a7cbaf..8e49fc478cd 100644
--- a/server/protocol.def
+++ b/server/protocol.def
@@ -3745,3 +3745,49 @@ struct handle_info
 @REPLY
     obj_handle_t handle;       /* next thread handle */
 @END
+
+
+enum fast_sync_type
+{
+    FAST_SYNC_SEMAPHORE = 1,
+    FAST_SYNC_MUTEX,
+    FAST_SYNC_EVENT,
+    FAST_SYNC_SERVER,
+    FAST_SYNC_QUEUE,
+};
+
+
+/* Obtain a handle to the fast synchronization device object */
+@REQ(get_fast_sync_device)
+@REPLY
+    obj_handle_t handle;          /* handle to the device */
+@END
+
+
+/* Get the fast synchronization object associated with the given handle */
+@REQ(get_fast_sync_obj)
+    obj_handle_t handle;          /* handle to the object */
+@REPLY
+    obj_handle_t handle;          /* handle to the fast synchronization object */
+    int          obj;             /* linux object */
+    int          type;            /* object type */
+    unsigned int access;          /* handle access rights */
+@END
+
+
+/* Begin a fast wait on a message queue */
+@REQ(fast_select_queue)
+    obj_handle_t handle;          /* handle to the queue */
+@END
+
+
+/* End a fast wait on a message queue */
+@REQ(fast_unselect_queue)
+    obj_handle_t handle;          /* handle to the queue */
+    int          signaled;        /* was the queue signaled? */
+@END
+
+
+/* Check if there are any user APCs queued */
+@REQ(check_user_apc)
+@END
diff --git a/server/queue.c b/server/queue.c
index e4903bcb79f..24770b1dd02 100644
--- a/server/queue.c
+++ b/server/queue.c
@@ -140,6 +140,8 @@ struct msg_queue
     struct thread_input   *input;           /* thread input descriptor */
     struct hook_table     *hooks;           /* hook table */
     timeout_t              last_get_msg;    /* time of last get message call */
+    struct fast_sync      *fast_sync;       /* fast synchronization object */
+    int                    in_fast_wait;    /* are we in a fast wait? */
 };
 
 struct hotkey
@@ -157,6 +159,7 @@ static int msg_queue_add_queue( struct object *obj, struct wait_queue_entry *ent
 static void msg_queue_remove_queue( struct object *obj, struct wait_queue_entry *entry );
 static int msg_queue_signaled( struct object *obj, struct wait_queue_entry *entry );
 static void msg_queue_satisfied( struct object *obj, struct wait_queue_entry *entry );
+static struct fast_sync *msg_queue_get_fast_sync( struct object *obj );
 static void msg_queue_destroy( struct object *obj );
 static void msg_queue_poll_event( struct fd *fd, int event );
 static void thread_input_dump( struct object *obj, int verbose );
@@ -183,6 +186,7 @@ static const struct object_ops msg_queue_ops =
     NULL,                      /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    msg_queue_get_fast_sync,   /* get_fast_sync */
     no_close_handle,           /* close_handle */
     msg_queue_destroy          /* destroy */
 };
@@ -220,6 +224,7 @@ static const struct object_ops thread_input_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_get_fast_sync,             /* get_fast_sync */
     no_close_handle,              /* close_handle */
     thread_input_destroy          /* destroy */
 };
@@ -305,6 +310,8 @@ static struct msg_queue *create_msg_queue( struct thread *thread, struct thread_
         queue->input           = (struct thread_input *)grab_object( input );
         queue->hooks           = NULL;
         queue->last_get_msg    = current_time;
+        queue->fast_sync       = NULL;
+        queue->in_fast_wait    = 0;
         list_init( &queue->send_result );
         list_init( &queue->callback_result );
         list_init( &queue->pending_timers );
@@ -480,7 +487,11 @@ static inline void set_queue_bits( struct msg_queue *queue, unsigned int bits )
 {
     queue->wake_bits |= bits;
     queue->changed_bits |= bits;
-    if (is_signaled( queue )) wake_up( &queue->obj, 0 );
+    if (is_signaled( queue ))
+    {
+        wake_up( &queue->obj, 0 );
+        fast_set_event( queue->fast_sync );
+    }
 }
 
 /* clear some queue bits */
@@ -488,6 +499,8 @@ static inline void clear_queue_bits( struct msg_queue *queue, unsigned int bits
 {
     queue->wake_bits &= ~bits;
     queue->changed_bits &= ~bits;
+    if (!is_signaled( queue ))
+        fast_reset_event( queue->fast_sync );
 }
 
 /* check whether msg is a keyboard message */
@@ -937,6 +950,10 @@ static int is_queue_hung( struct msg_queue *queue )
         if (get_wait_queue_thread(entry)->queue == queue)
             return 0;  /* thread is waiting on queue -> not hung */
     }
+
+    if (queue->in_fast_wait)
+        return 0;  /* thread is waiting on queue in absentia -> not hung */
+
     return 1;
 }
 
@@ -997,6 +1014,17 @@ static void msg_queue_satisfied( struct object *obj, struct wait_queue_entry *en
     struct msg_queue *queue = (struct msg_queue *)obj;
     queue->wake_mask = 0;
     queue->changed_mask = 0;
+    fast_reset_event( queue->fast_sync );
+}
+
+static struct fast_sync *msg_queue_get_fast_sync( struct object *obj )
+{
+    struct msg_queue *queue = (struct msg_queue *)obj;
+
+    if (!queue->fast_sync)
+        queue->fast_sync = fast_create_event( FAST_SYNC_QUEUE, 1, is_signaled( queue ) );
+    if (queue->fast_sync) grab_object( queue->fast_sync );
+    return queue->fast_sync;
 }
 
 static void msg_queue_destroy( struct object *obj )
@@ -1035,6 +1063,7 @@ static void msg_queue_destroy( struct object *obj )
     release_object( queue->input );
     if (queue->hooks) release_object( queue->hooks );
     if (queue->fd) release_object( queue->fd );
+    if (queue->fast_sync) release_object( queue->fast_sync );
 }
 
 static void msg_queue_poll_event( struct fd *fd, int event )
@@ -1045,6 +1074,7 @@ static void msg_queue_poll_event( struct fd *fd, int event )
     if (event & (POLLERR | POLLHUP)) set_fd_events( fd, -1 );
     else set_fd_events( queue->fd, 0 );
     wake_up( &queue->obj, 0 );
+    fast_set_event( queue->fast_sync );
 }
 
 static void thread_input_dump( struct object *obj, int verbose )
@@ -2421,8 +2451,20 @@ DECL_HANDLER(set_queue_mask)
         if (is_signaled( queue ))
         {
             /* if skip wait is set, do what would have been done in the subsequent wait */
-            if (req->skip_wait) queue->wake_mask = queue->changed_mask = 0;
-            else wake_up( &queue->obj, 0 );
+            if (req->skip_wait)
+            {
+                queue->wake_mask = queue->changed_mask = 0;
+                fast_reset_event( queue->fast_sync );
+            }
+            else
+            {
+                wake_up( &queue->obj, 0 );
+                fast_set_event( queue->fast_sync );
+            }
+        }
+        else
+        {
+            fast_reset_event( queue->fast_sync );
         }
     }
 }
@@ -2437,6 +2479,8 @@ DECL_HANDLER(get_queue_status)
         reply->wake_bits    = queue->wake_bits;
         reply->changed_bits = queue->changed_bits;
         queue->changed_bits &= ~req->clear_bits;
+        if (!is_signaled( queue ))
+            fast_reset_event( queue->fast_sync );
     }
     else reply->wake_bits = reply->changed_bits = 0;
 }
@@ -2620,6 +2664,9 @@ DECL_HANDLER(get_message)
     if (filter & QS_INPUT) queue->changed_bits &= ~QS_INPUT;
     if (filter & QS_PAINT) queue->changed_bits &= ~QS_PAINT;
 
+    if (!is_signaled( queue ))
+        fast_reset_event( queue->fast_sync );
+
     /* then check for posted messages */
     if ((filter & QS_POSTMESSAGE) &&
         get_posted_message( queue, get_win, req->get_first, req->get_last, req->flags, reply ))
@@ -2673,6 +2720,7 @@ DECL_HANDLER(get_message)
     if (get_win == -1 && current->process->idle_event) set_event( current->process->idle_event );
     queue->wake_mask = req->wake_mask;
     queue->changed_mask = req->changed_mask;
+    fast_reset_event( queue->fast_sync );
     set_error( STATUS_PENDING );  /* FIXME */
 }
 
@@ -3394,3 +3442,61 @@ DECL_HANDLER(get_rawinput_devices)
             devices[i++] = e->device;
     }
 }
+
+DECL_HANDLER(fast_select_queue)
+{
+    struct msg_queue *queue;
+
+    if (!(queue = (struct msg_queue *)get_handle_obj( current->process, req->handle,
+                                                      SYNCHRONIZE, &msg_queue_ops )))
+        return;
+
+    /* a thread can only wait on its own queue */
+    if (current->queue != queue || queue->in_fast_wait)
+    {
+        set_error( STATUS_ACCESS_DENIED );
+    }
+    else
+    {
+        if (current->process->idle_event && !(queue->wake_mask & QS_SMRESULT))
+            set_event( current->process->idle_event );
+
+        if (queue->fd)
+            set_fd_events( queue->fd, POLLIN );
+
+        queue->in_fast_wait = 1;
+    }
+
+    release_object( queue );
+}
+
+DECL_HANDLER(fast_unselect_queue)
+{
+    struct msg_queue *queue;
+
+    if (!(queue = (struct msg_queue *)get_handle_obj( current->process, req->handle,
+                                                      SYNCHRONIZE, &msg_queue_ops )))
+        return;
+
+    if (current->queue != queue || !queue->in_fast_wait)
+    {
+        set_error( STATUS_ACCESS_DENIED );
+    }
+    else
+    {
+        if (queue->fd)
+            set_fd_events( queue->fd, 0 );
+
+        if (req->signaled)
+            msg_queue_satisfied( &queue->obj, NULL );
+
+        queue->in_fast_wait = 0;
+    }
+
+    release_object( queue );
+}
+
+DECL_HANDLER(check_user_apc)
+{
+    if (list_empty( &current->user_apc )) set_error( STATUS_TIMEOUT );
+}
diff --git a/server/registry.c b/server/registry.c
index 68ec4f9e39a..c9110c56e6e 100644
--- a/server/registry.c
+++ b/server/registry.c
@@ -188,6 +188,7 @@ static const struct object_ops key_ops =
     NULL,                    /* unlink_name */
     no_open_file,            /* open_file */
     no_kernel_obj_list,      /* get_kernel_obj_list */
+    no_get_fast_sync,        /* get_fast_sync */
     key_close_handle,        /* close_handle */
     key_destroy              /* destroy */
 };
diff --git a/server/request.c b/server/request.c
index 29b63600f15..ae6d9d0b52c 100644
--- a/server/request.c
+++ b/server/request.c
@@ -109,6 +109,7 @@ static const struct object_ops master_socket_ops =
     NULL,                          /* unlink_name */
     no_open_file,                  /* open_file */
     no_kernel_obj_list,            /* get_kernel_obj_list */
+    no_get_fast_sync,              /* get_fast_sync */
     no_close_handle,               /* close_handle */
     master_socket_destroy          /* destroy */
 };
diff --git a/server/request.h b/server/request.h
index a8d74f01f96..1c778fce75f 100644
--- a/server/request.h
+++ b/server/request.h
@@ -395,6 +395,11 @@ DECL_HANDLER(terminate_job);
 DECL_HANDLER(suspend_process);
 DECL_HANDLER(resume_process);
 DECL_HANDLER(get_next_thread);
+DECL_HANDLER(get_fast_sync_device);
+DECL_HANDLER(get_fast_sync_obj);
+DECL_HANDLER(fast_select_queue);
+DECL_HANDLER(fast_unselect_queue);
+DECL_HANDLER(check_user_apc);
 
 #ifdef WANT_REQUEST_HANDLERS
 
@@ -677,6 +682,11 @@ static const req_handler req_handlers[REQ_NB_REQUESTS] =
     (req_handler)req_suspend_process,
     (req_handler)req_resume_process,
     (req_handler)req_get_next_thread,
+    (req_handler)req_get_fast_sync_device,
+    (req_handler)req_get_fast_sync_obj,
+    (req_handler)req_fast_select_queue,
+    (req_handler)req_fast_unselect_queue,
+    (req_handler)req_check_user_apc,
 };
 
 C_ASSERT( sizeof(abstime_t) == 8 );
@@ -2258,6 +2268,22 @@ C_ASSERT( FIELD_OFFSET(struct get_next_thread_request, flags) == 28 );
 C_ASSERT( sizeof(struct get_next_thread_request) == 32 );
 C_ASSERT( FIELD_OFFSET(struct get_next_thread_reply, handle) == 8 );
 C_ASSERT( sizeof(struct get_next_thread_reply) == 16 );
+C_ASSERT( sizeof(struct get_fast_sync_device_request) == 16 );
+C_ASSERT( FIELD_OFFSET(struct get_fast_sync_device_reply, handle) == 8 );
+C_ASSERT( sizeof(struct get_fast_sync_device_reply) == 16 );
+C_ASSERT( FIELD_OFFSET(struct get_fast_sync_obj_request, handle) == 12 );
+C_ASSERT( sizeof(struct get_fast_sync_obj_request) == 16 );
+C_ASSERT( FIELD_OFFSET(struct get_fast_sync_obj_reply, handle) == 8 );
+C_ASSERT( FIELD_OFFSET(struct get_fast_sync_obj_reply, obj) == 12 );
+C_ASSERT( FIELD_OFFSET(struct get_fast_sync_obj_reply, type) == 16 );
+C_ASSERT( FIELD_OFFSET(struct get_fast_sync_obj_reply, access) == 20 );
+C_ASSERT( sizeof(struct get_fast_sync_obj_reply) == 24 );
+C_ASSERT( FIELD_OFFSET(struct fast_select_queue_request, handle) == 12 );
+C_ASSERT( sizeof(struct fast_select_queue_request) == 16 );
+C_ASSERT( FIELD_OFFSET(struct fast_unselect_queue_request, handle) == 12 );
+C_ASSERT( FIELD_OFFSET(struct fast_unselect_queue_request, signaled) == 16 );
+C_ASSERT( sizeof(struct fast_unselect_queue_request) == 24 );
+C_ASSERT( sizeof(struct check_user_apc_request) == 16 );
 
 #endif  /* WANT_REQUEST_HANDLERS */
 
diff --git a/server/semaphore.c b/server/semaphore.c
index 543d5883ec8..6b7e737c848 100644
--- a/server/semaphore.c
+++ b/server/semaphore.c
@@ -55,12 +55,15 @@ struct semaphore
     struct object  obj;    /* object header */
     unsigned int   count;  /* current count */
     unsigned int   max;    /* maximum possible count */
+    struct fast_sync *fast_sync; /* fast synchronization object */
 };
 
 static void semaphore_dump( struct object *obj, int verbose );
 static int semaphore_signaled( struct object *obj, struct wait_queue_entry *entry );
 static void semaphore_satisfied( struct object *obj, struct wait_queue_entry *entry );
 static int semaphore_signal( struct object *obj, unsigned int access );
+static struct fast_sync *semaphore_get_fast_sync( struct object *obj );
+static void semaphore_destroy( struct object *obj );
 
 static const struct object_ops semaphore_ops =
 {
@@ -82,8 +85,9 @@ static const struct object_ops semaphore_ops =
     default_unlink_name,           /* unlink_name */
     no_open_file,                  /* open_file */
     no_kernel_obj_list,            /* get_kernel_obj_list */
+    semaphore_get_fast_sync,       /* get_fast_sync */
     no_close_handle,               /* close_handle */
-    no_destroy                     /* destroy */
+    semaphore_destroy              /* destroy */
 };
 
 
@@ -105,6 +109,7 @@ static struct semaphore *create_semaphore( struct object *root, const struct uni
             /* initialize it if it didn't already exist */
             sem->count = initial;
             sem->max   = max;
+            sem->fast_sync = NULL;
         }
     }
     return sem;
@@ -167,6 +172,23 @@ static int semaphore_signal( struct object *obj, unsigned int access )
     return release_semaphore( sem, 1, NULL );
 }
 
+static struct fast_sync *semaphore_get_fast_sync( struct object *obj )
+{
+    struct semaphore *semaphore = (struct semaphore *)obj;
+
+    if (!semaphore->fast_sync)
+        semaphore->fast_sync = fast_create_semaphore( semaphore->count, semaphore->max );
+    if (semaphore->fast_sync) grab_object( semaphore->fast_sync );
+    return semaphore->fast_sync;
+}
+
+static void semaphore_destroy( struct object *obj )
+{
+    struct semaphore *semaphore = (struct semaphore *)obj;
+
+    if (semaphore->fast_sync) release_object( semaphore->fast_sync );
+}
+
 /* create a semaphore */
 DECL_HANDLER(create_semaphore)
 {
diff --git a/server/serial.c b/server/serial.c
index d3ea4cbe420..8c68aafe61f 100644
--- a/server/serial.c
+++ b/server/serial.c
@@ -104,6 +104,7 @@ static const struct object_ops serial_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    default_fd_get_fast_sync,     /* get_fast_sync */
     no_close_handle,              /* close_handle */
     serial_destroy                /* destroy */
 };
diff --git a/server/signal.c b/server/signal.c
index 0c22c157f2b..ad555fd51af 100644
--- a/server/signal.c
+++ b/server/signal.c
@@ -79,6 +79,7 @@ static const struct object_ops handler_ops =
     NULL,                     /* unlink_name */
     no_open_file,             /* open_file */
     no_kernel_obj_list,       /* get_kernel_obj_list */
+    no_get_fast_sync,         /* get_fast_sync */
     no_close_handle,          /* close_handle */
     handler_destroy           /* destroy */
 };
diff --git a/server/sock.c b/server/sock.c
index b4649abbf08..855454f05ee 100644
--- a/server/sock.c
+++ b/server/sock.c
@@ -214,6 +214,7 @@ static const struct object_ops sock_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    default_fd_get_fast_sync,     /* get_fast_sync */
     sock_close_handle,            /* close_handle */
     sock_destroy                  /* destroy */
 };
@@ -2072,6 +2073,7 @@ static const struct object_ops ifchange_ops =
     NULL,                    /* unlink_name */
     no_open_file,            /* open_file */
     no_kernel_obj_list,      /* get_kernel_obj_list */
+    no_get_fast_sync,        /* get_fast_sync */
     no_close_handle,         /* close_handle */
     ifchange_destroy         /* destroy */
 };
@@ -2292,6 +2294,7 @@ static const struct object_ops socket_device_ops =
     default_unlink_name,        /* unlink_name */
     socket_device_open_file,    /* open_file */
     no_kernel_obj_list,         /* get_kernel_obj_list */
+    no_get_fast_sync,           /* get_fast_sync */
     no_close_handle,            /* close_handle */
     no_destroy                  /* destroy */
 };
diff --git a/server/symlink.c b/server/symlink.c
index 3879bb685f7..241e13fa369 100644
--- a/server/symlink.c
+++ b/server/symlink.c
@@ -84,6 +84,7 @@ static const struct object_ops symlink_ops =
     default_unlink_name,          /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_get_fast_sync,             /* get_fast_sync */
     no_close_handle,              /* close_handle */
     symlink_destroy               /* destroy */
 };
diff --git a/server/thread.c b/server/thread.c
index 0c7f11c0da1..0cae26c0653 100644
--- a/server/thread.c
+++ b/server/thread.c
@@ -109,6 +109,7 @@ static const struct object_ops thread_apc_ops =
     NULL,                       /* unlink_name */
     no_open_file,               /* open_file */
     no_kernel_obj_list,         /* get_kernel_obj_list */
+    no_get_fast_sync,           /* get_fast_sync */
     no_close_handle,            /* close_handle */
     thread_apc_destroy          /* destroy */
 };
@@ -146,6 +147,7 @@ static const struct object_ops context_ops =
     NULL,                       /* unlink_name */
     no_open_file,               /* open_file */
     no_kernel_obj_list,         /* get_kernel_obj_list */
+    no_get_fast_sync,           /* get_fast_sync */
     no_close_handle,            /* close_handle */
     no_destroy                  /* destroy */
 };
@@ -173,6 +175,7 @@ static int thread_signaled( struct object *obj, struct wait_queue_entry *entry )
 static unsigned int thread_map_access( struct object *obj, unsigned int access );
 static void thread_poll_event( struct fd *fd, int event );
 static struct list *thread_get_kernel_obj_list( struct object *obj );
+static struct fast_sync *thread_get_fast_sync( struct object *obj );
 static void destroy_thread( struct object *obj );
 
 static const struct object_ops thread_ops =
@@ -195,6 +198,7 @@ static const struct object_ops thread_ops =
     NULL,                       /* unlink_name */
     no_open_file,               /* open_file */
     thread_get_kernel_obj_list, /* get_kernel_obj_list */
+    thread_get_fast_sync,       /* get_fast_sync */
     no_close_handle,            /* close_handle */
     destroy_thread              /* destroy */
 };
@@ -242,6 +246,7 @@ static inline void init_thread_structure( struct thread *thread )
     thread->token           = NULL;
     thread->desc            = NULL;
     thread->desc_len        = 0;
+    thread->fast_sync       = NULL;
 
     thread->creation_time = current_time;
     thread->exit_time     = 0;
@@ -391,6 +396,16 @@ static struct list *thread_get_kernel_obj_list( struct object *obj )
     return &thread->kernel_object;
 }
 
+static struct fast_sync *thread_get_fast_sync( struct object *obj )
+{
+    struct thread *thread = (struct thread *)obj;
+
+    if (!thread->fast_sync)
+        thread->fast_sync = fast_create_event( FAST_SYNC_SERVER, 1, thread->state == TERMINATED );
+    if (thread->fast_sync) grab_object( thread->fast_sync );
+    return thread->fast_sync;
+}
+
 /* cleanup everything that is no longer needed by a dead thread */
 /* used by destroy_thread and kill_thread */
 static void cleanup_thread( struct thread *thread )
@@ -445,6 +460,7 @@ static void destroy_thread( struct object *obj )
     release_object( thread->process );
     if (thread->id) free_ptid( thread->id );
     if (thread->token) release_object( thread->token );
+    if (thread->fast_sync) release_object( thread->fast_sync );
 }
 
 /* dump a thread on stdout for debugging purposes */
@@ -1125,8 +1141,9 @@ static int queue_apc( struct process *process, struct thread *thread, struct thr
     {
         if (thread->state == TERMINATED) return 0;
         if (!(queue = get_apc_queue( thread, apc->call.type ))) return 1;
-        /* send signal for system APCs if needed */
-        if (queue == &thread->system_apc && list_empty( queue ) && !is_in_apc_wait( thread ))
+        /* send signal if needed */
+        if ((queue == &thread->system_apc || fast_user_apc_needs_signal())
+            && list_empty( queue ) && !is_in_apc_wait( thread ))
         {
             if (!send_thread_signal( thread, SIGUSR1 )) return 0;
         }
@@ -1279,7 +1296,9 @@ void kill_thread( struct thread *thread, int violent_death )
     }
     kill_console_processes( thread, 0 );
     abandon_mutexes( thread );
+    fast_abandon_mutexes( thread->id );
     wake_up( &thread->obj, 0 );
+    fast_set_event( thread->fast_sync );
     if (violent_death) send_thread_signal( thread, SIGQUIT );
     cleanup_thread( thread );
     remove_process_thread( thread->process, thread );
diff --git a/server/thread.h b/server/thread.h
index 8dcf966a90a..caabbe5bfd6 100644
--- a/server/thread.h
+++ b/server/thread.h
@@ -90,6 +90,7 @@ struct thread
     struct list            kernel_object; /* list of kernel object pointers */
     data_size_t            desc_len;      /* thread description length in bytes */
     WCHAR                 *desc;          /* thread description string */
+    struct fast_sync      *fast_sync;     /* fast synchronization object */
 };
 
 extern struct thread *current;
diff --git a/server/timer.c b/server/timer.c
index 5e265d2ddf6..4f9e5e61aa1 100644
--- a/server/timer.c
+++ b/server/timer.c
@@ -62,11 +62,13 @@ struct timer
     struct thread       *thread;    /* thread that set the APC function */
     client_ptr_t         callback;  /* callback APC function */
     client_ptr_t         arg;       /* callback argument */
+    struct fast_sync    *fast_sync; /* fast synchronization object */
 };
 
 static void timer_dump( struct object *obj, int verbose );
 static int timer_signaled( struct object *obj, struct wait_queue_entry *entry );
 static void timer_satisfied( struct object *obj, struct wait_queue_entry *entry );
+static struct fast_sync *timer_get_fast_sync( struct object *obj );
 static void timer_destroy( struct object *obj );
 
 static const struct object_ops timer_ops =
@@ -89,6 +91,7 @@ static const struct object_ops timer_ops =
     default_unlink_name,       /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    timer_get_fast_sync,       /* get_fast_sync */
     no_close_handle,           /* close_handle */
     timer_destroy              /* destroy */
 };
@@ -111,6 +114,7 @@ static struct timer *create_timer( struct object *root, const struct unicode_str
             timer->period   = 0;
             timer->timeout  = NULL;
             timer->thread   = NULL;
+            timer->fast_sync = NULL;
         }
     }
     return timer;
@@ -152,6 +156,7 @@ static void timer_callback( void *private )
     /* wake up waiters */
     timer->signaled = 1;
     wake_up( &timer->obj, 0 );
+    fast_set_event( timer->fast_sync );
 }
 
 /* cancel a running timer */
@@ -182,6 +187,7 @@ static int set_timer( struct timer *timer, timeout_t expire, unsigned int period
     {
         period = 0;  /* period doesn't make any sense for a manual timer */
         timer->signaled = 0;
+        fast_reset_event( timer->fast_sync );
     }
     timer->when     = (expire <= 0) ? expire - monotonic_time : max( expire, current_time );
     timer->period   = period;
@@ -216,6 +222,16 @@ static void timer_satisfied( struct object *obj, struct wait_queue_entry *entry
     if (!timer->manual) timer->signaled = 0;
 }
 
+static struct fast_sync *timer_get_fast_sync( struct object *obj )
+{
+    struct timer *timer = (struct timer *)obj;
+
+    if (!timer->fast_sync)
+        timer->fast_sync = fast_create_event( FAST_SYNC_SERVER, timer->manual, timer->signaled );
+    if (timer->fast_sync) grab_object( timer->fast_sync );
+    return timer->fast_sync;
+}
+
 static void timer_destroy( struct object *obj )
 {
     struct timer *timer = (struct timer *)obj;
@@ -223,6 +239,7 @@ static void timer_destroy( struct object *obj )
 
     if (timer->timeout) remove_timeout_user( timer->timeout );
     if (timer->thread) release_object( timer->thread );
+    if (timer->fast_sync) release_object( timer->fast_sync );
 }
 
 /* create a timer */
diff --git a/server/token.c b/server/token.c
index ad5d7cda323..7d73e9d7caa 100644
--- a/server/token.c
+++ b/server/token.c
@@ -173,6 +173,7 @@ static const struct object_ops token_ops =
     NULL,                      /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    no_get_fast_sync,          /* get_fast_sync */
     no_close_handle,           /* close_handle */
     token_destroy              /* destroy */
 };
diff --git a/server/trace.c b/server/trace.c
index 1c51bffe1aa..e7b760b4634 100644
--- a/server/trace.c
+++ b/server/trace.c
@@ -4545,6 +4545,43 @@ static void dump_get_next_thread_reply( const struct get_next_thread_reply *req
     fprintf( stderr, " handle=%04x", req->handle );
 }
 
+static void dump_get_fast_sync_device_request( const struct get_fast_sync_device_request *req )
+{
+}
+
+static void dump_get_fast_sync_device_reply( const struct get_fast_sync_device_reply *req )
+{
+    fprintf( stderr, " handle=%04x", req->handle );
+}
+
+static void dump_get_fast_sync_obj_request( const struct get_fast_sync_obj_request *req )
+{
+    fprintf( stderr, " handle=%04x", req->handle );
+}
+
+static void dump_get_fast_sync_obj_reply( const struct get_fast_sync_obj_reply *req )
+{
+    fprintf( stderr, " handle=%04x", req->handle );
+    fprintf( stderr, ", obj=%d", req->obj );
+    fprintf( stderr, ", type=%d", req->type );
+    fprintf( stderr, ", access=%08x", req->access );
+}
+
+static void dump_fast_select_queue_request( const struct fast_select_queue_request *req )
+{
+    fprintf( stderr, " handle=%04x", req->handle );
+}
+
+static void dump_fast_unselect_queue_request( const struct fast_unselect_queue_request *req )
+{
+    fprintf( stderr, " handle=%04x", req->handle );
+    fprintf( stderr, ", signaled=%d", req->signaled );
+}
+
+static void dump_check_user_apc_request( const struct check_user_apc_request *req )
+{
+}
+
 static const dump_func req_dumpers[REQ_NB_REQUESTS] = {
     (dump_func)dump_new_process_request,
     (dump_func)dump_get_new_process_info_request,
@@ -4822,6 +4859,11 @@ static const dump_func req_dumpers[REQ_NB_REQUESTS] = {
     (dump_func)dump_suspend_process_request,
     (dump_func)dump_resume_process_request,
     (dump_func)dump_get_next_thread_request,
+    (dump_func)dump_get_fast_sync_device_request,
+    (dump_func)dump_get_fast_sync_obj_request,
+    (dump_func)dump_fast_select_queue_request,
+    (dump_func)dump_fast_unselect_queue_request,
+    (dump_func)dump_check_user_apc_request,
 };
 
 static const dump_func reply_dumpers[REQ_NB_REQUESTS] = {
@@ -5101,6 +5143,11 @@ static const dump_func reply_dumpers[REQ_NB_REQUESTS] = {
     NULL,
     NULL,
     (dump_func)dump_get_next_thread_reply,
+    (dump_func)dump_get_fast_sync_device_reply,
+    (dump_func)dump_get_fast_sync_obj_reply,
+    NULL,
+    NULL,
+    NULL,
 };
 
 static const char * const req_names[REQ_NB_REQUESTS] = {
@@ -5380,6 +5427,11 @@ static const char * const req_names[REQ_NB_REQUESTS] = {
     "suspend_process",
     "resume_process",
     "get_next_thread",
+    "get_fast_sync_device",
+    "get_fast_sync_obj",
+    "fast_select_queue",
+    "fast_unselect_queue",
+    "check_user_apc",
 };
 
 static const struct
diff --git a/server/winstation.c b/server/winstation.c
index 61f9f77c73f..2dee8067dd2 100644
--- a/server/winstation.c
+++ b/server/winstation.c
@@ -87,6 +87,7 @@ static const struct object_ops winstation_ops =
     default_unlink_name,          /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_get_fast_sync,             /* get_fast_sync */
     winstation_close_handle,      /* close_handle */
     winstation_destroy            /* destroy */
 };
@@ -127,6 +128,7 @@ static const struct object_ops desktop_ops =
     default_unlink_name,          /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_get_fast_sync,             /* get_fast_sync */
     desktop_close_handle,         /* close_handle */
     desktop_destroy               /* destroy */
 };