diff --git a/src/core/ngx_spinlock.c b/src/core/ngx_spinlock.c
new file mode 100644
index 0000000..c3c65d3
--- /dev/null
+++ b/src/core/ngx_spinlock.c
@@ -0,0 +1,29 @@
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+
+
+void ngx_spinlock(ngx_atomic_t *lock, ngx_uint_t spin)
+{
+    ngx_uint_t  tries;
+
+    tries = 0;
+
+    for ( ;; ) {
+
+        if (*lock) {
+            if (ngx_ncpu > 1 && tries++ < spin) {
+                continue;
+            }
+
+            ngx_sched_yield();
+
+            tries = 0;
+
+        } else {
+            if (ngx_atomic_cmp_set(lock, 0, 1)) {
+                return;
+            }
+        }
+    }
+}
diff --git a/src/event/modules/ngx_kqueue_module.c b/src/event/modules/ngx_kqueue_module.c
index cc84d2e..379e530 100644
--- a/src/event/modules/ngx_kqueue_module.c
+++ b/src/event/modules/ngx_kqueue_module.c
@@ -506,7 +506,6 @@
 
             instance = (uintptr_t) ev & 1;
             ev = (ngx_event_t *) ((uintptr_t) ev & (uintptr_t) ~1);
-            ev->returned_instance = instance;
 
             if (!ev->active || ev->instance != instance) {
 
@@ -520,6 +519,8 @@
                 continue;
             }
 
+            ev->returned_instance = instance;
+
             if (ev->log && (ev->log->log_level & NGX_LOG_DEBUG_CONNECTION)) {
                 ngx_kqueue_dump_event(ev->log, &event_list[i]);
             }
diff --git a/src/event/ngx_event_accept.c b/src/event/ngx_event_accept.c
index 984570f..18f8586 100644
--- a/src/event/ngx_event_accept.c
+++ b/src/event/ngx_event_accept.c
@@ -210,10 +210,31 @@
         rinstance = rev->returned_instance;
         winstance = wev->returned_instance;
 
+#if (NGX_THREADS)
+
+        /*
+         * We has to acquire the lock to avoid the race condition when
+         * the connection was just closed by another thread but its lock
+         * is not unlocked at this point and we got the same descriptor.
+         *
+         * The condition should be too rare.
+         */
+
+        if (ngx_trylock(&c->lock) == 0) {
+
+            /* TODO: ngx_cycle->stat.accept.spinlock++; */
+
+            ngx_spinlock(&c->lock, 1000);
+        }
+
+#endif
+
         ngx_memzero(rev, sizeof(ngx_event_t));
         ngx_memzero(wev, sizeof(ngx_event_t));
         ngx_memzero(c, sizeof(ngx_connection_t));
 
+        /* ngx_memzero(c) does ngx_unlock(&c->lock); */
+
         c->pool = pool;
 
         c->listening = ls->listening;
diff --git a/src/event/ngx_event_posted.c b/src/event/ngx_event_posted.c
index 795aa61..0c91f4e 100644
--- a/src/event/ngx_event_posted.c
+++ b/src/event/ngx_event_posted.c
@@ -111,6 +111,9 @@
 
             if (ev->posted) {
                 ev->posted = 0;
+                if (!ev->timedout) {
+                    ev->ready = 1;
+                }
             }
 
             ev->event_handler(ev);
diff --git a/src/event/ngx_event_posted.h b/src/event/ngx_event_posted.h
index c2945c4..5059fa9 100644
--- a/src/event/ngx_event_posted.h
+++ b/src/event/ngx_event_posted.h
@@ -7,6 +7,19 @@
 #include <ngx_event.h>
 
 
+typedef struct ngx_posted_events_s  ngx_posted_event_t;
+
+struct ngx_posted_events_s {
+    ngx_event_t         *event;
+    ngx_posted_event_t  *next;
+
+    unsigned             instance:1;
+    unsigned             ready:1;
+    unsigned             timedout:1;
+    unsigned             complete:1;
+};
+
+
 #define ngx_post_event(ev)                                                    \
             if (!ev->posted) {                                                \
                 ev->next = (ngx_event_t *) ngx_posted_events;                 \
@@ -14,6 +27,27 @@
                 ev->posted = 1;                                               \
             }
 
+/*
+\
+   ngx_log_debug3(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, \
+               "POST: %08X %08X %08X", ngx_posted_events, \
+               (ngx_posted_events ? ngx_posted_events->next: 0), \
+               ((ngx_posted_events && ngx_posted_events->next) ? \
+                               ngx_posted_events->next->next: 0)); \
+\
+*/
+
+/*
+\
+{ int i; ngx_event_t *e;\
+  e = (ngx_event_t *) ngx_posted_events; \
+for (i = 0; e && i < 10; e = e->next, i++) { \
+   ngx_log_debug2(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, \
+                  "POST: %d %08X", i, e);\
+}} \
+\
+*/
+
 
 void ngx_event_process_posted(ngx_cycle_t *cycle);
 
diff --git a/src/event/ngx_event_spinlock.c b/src/event/ngx_event_spinlock.c
deleted file mode 100644
index 58edb2a..0000000
--- a/src/event/ngx_event_spinlock.c
+++ /dev/null
@@ -1,26 +0,0 @@
-
-
-void _spinlock(ngx_atomic_t *lock)
-{
-    ngx_int_t  tries;
-
-    tries = 0;
-
-    for ( ;; ) {
-
-        if (*lock) {
-            if (ngx_ncpu > 1 && tries++ < 1000) {
-                continue;
-            }
-
-            sched_yield();
-            tries = 0;
-
-        } else {
-            if (ngx_atomic_cmp_set(lock, 0, 1)) {
-                return;
-            }
-        }
-    }
-}
-
diff --git a/src/core/ngx_atomic.h b/src/os/unix/ngx_atomic.h
similarity index 73%
rename from src/core/ngx_atomic.h
rename to src/os/unix/ngx_atomic.h
index a149ad2..18d5eda 100644
--- a/src/core/ngx_atomic.h
+++ b/src/os/unix/ngx_atomic.h
@@ -68,24 +68,6 @@
 }
 
 
-#elif (WIN32)
-
-#define ngx_atomic_inc(p)       InterlockedIncrement((long *) p)
-#define ngx_atomic_dec(p)       InterlockedDecrement((long *) p)
-
-#if defined(__WATCOMC__) || defined(__BORLANDC__)
-
-#define ngx_atomic_cmp_set(lock, old, set)                                    \
-     (InterlockedCompareExchange((long *) lock, set, old) == old)
-
-#else
-
-#define ngx_atomic_cmp_set(lock, old, set)                                    \
-     (InterlockedCompareExchange((void **) lock, (void *) set, (void *) old)  \
-      == (void *) old)
-
-#endif
-
 #else
 
 typedef volatile uint32_t  ngx_atomic_t;
@@ -99,6 +81,8 @@
 #endif
 
 
+void ngx_spinlock(ngx_atomic_t *lock, ngx_uint_t spin);
+
 #define ngx_trylock(lock)  (*(lock) == 0 && ngx_atomic_cmp_set(lock, 0, 1))
 #define ngx_unlock(lock)    *(lock) = 0
 
diff --git a/src/os/unix/ngx_freebsd_init.c b/src/os/unix/ngx_freebsd_init.c
index 35be164..5addd26 100644
--- a/src/os/unix/ngx_freebsd_init.c
+++ b/src/os/unix/ngx_freebsd_init.c
@@ -8,6 +8,7 @@
 char ngx_freebsd_kern_osrelease[20];
 int ngx_freebsd_kern_osreldate;
 int ngx_freebsd_hw_ncpu;
+int ngx_freebsd_machdep_hlt_logical_cpus;
 int ngx_freebsd_net_inet_tcp_sendspace;
 int ngx_freebsd_sendfile_nbytes_bug;
 int ngx_freebsd_use_tcp_nopush;
@@ -42,6 +43,10 @@
      &ngx_freebsd_hw_ncpu,
      sizeof(int)},
 
+    {"machdep.hlt_logical_cpus",
+     &ngx_freebsd_machdep_hlt_logical_cpus,
+     sizeof(int)},
+
     {"net.inet.tcp.sendspace",
      &ngx_freebsd_net_inet_tcp_sendspace,
      sizeof(int)},
@@ -166,6 +171,10 @@
                                                                        == -1) {
             err = errno;
             if (err != NGX_ENOENT) {
+                if (sysctls[i].value == &ngx_freebsd_machdep_hlt_logical_cpus) {
+                    continue;
+                }
+
                 ngx_log_error(NGX_LOG_ALERT, log, err,
                               "sysctlbyname(%s) failed", sysctls[i].name);
                 return NGX_ERROR;
@@ -177,5 +186,11 @@
         }
     }
 
+    if (ngx_freebsd_machdep_hlt_logical_cpus) {
+        ngx_ncpu = ngx_freebsd_hw_ncpu / 2;
+    } else {
+        ngx_ncpu = ngx_freebsd_hw_ncpu;
+    }
+
     return ngx_posix_init(log);
 }
diff --git a/src/os/unix/ngx_os.h b/src/os/unix/ngx_os.h
index d9a1a45..c4da5cd 100644
--- a/src/os/unix/ngx_os.h
+++ b/src/os/unix/ngx_os.h
@@ -47,6 +47,7 @@
 
 
 extern ngx_os_io_t  ngx_os_io;
+extern int          ngx_ncpu;
 extern int          ngx_max_sockets;
 extern int          ngx_inherited_nonblocking;
 
diff --git a/src/os/unix/ngx_posix_init.c b/src/os/unix/ngx_posix_init.c
index f94ffff..7498ae6 100644
--- a/src/os/unix/ngx_posix_init.c
+++ b/src/os/unix/ngx_posix_init.c
@@ -3,6 +3,7 @@
 #include <ngx_core.h>
 
 
+int  ngx_ncpu;
 int  ngx_max_sockets;
 int  ngx_inherited_nonblocking;
 
@@ -84,6 +85,10 @@
 
     ngx_pagesize = getpagesize();
 
+    if (ngx_ncpu == 0) {
+        ngx_ncpu = 1;
+    }
+
     for (sig = signals; sig->signo != 0; sig++) {
         ngx_memzero(&sa, sizeof(struct sigaction));
         sa.sa_handler = sig->handler;
diff --git a/src/os/unix/ngx_process.h b/src/os/unix/ngx_process.h
index ccea40d..66ef38d 100644
--- a/src/os/unix/ngx_process.h
+++ b/src/os/unix/ngx_process.h
@@ -49,6 +49,8 @@
 void ngx_process_get_status(void);
 void ngx_close_channel(ngx_fd_t *fd, ngx_log_t *log);
 
+#define ngx_sched_yield()  sched_yield()
+
 
 extern ngx_pid_t      ngx_pid;
 extern ngx_socket_t   ngx_channel;
diff --git a/src/os/win32/ngx_atomic.h b/src/os/win32/ngx_atomic.h
new file mode 100644
index 0000000..fcc3ff1
--- /dev/null
+++ b/src/os/win32/ngx_atomic.h
@@ -0,0 +1,33 @@
+#ifndef _NGX_ATOMIC_H_INCLUDED_
+#define _NGX_ATOMIC_H_INCLUDED_
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+
+
+#define ngx_atomic_inc(p)       InterlockedIncrement((long *) p)
+#define ngx_atomic_dec(p)       InterlockedDecrement((long *) p)
+
+
+#if defined( __WATCOMC__ ) || defined( __BORLANDC__ )
+
+#define ngx_atomic_cmp_set(lock, old, set)                                    \
+     (InterlockedCompareExchange((long *) lock, set, old) == old)
+
+#else
+
+#define ngx_atomic_cmp_set(lock, old, set)                                    \
+     (InterlockedCompareExchange((void **) lock, (void *) set, (void *) old)  \
+      == (void *) old)
+
+#endif
+
+
+void ngx_spinlock(ngx_atomic_t *lock, ngx_uint_t spin);
+
+#define ngx_trylock(lock)  (*(lock) == 0 && ngx_atomic_cmp_set(lock, 0, 1))
+#define ngx_unlock(lock)    *(lock) = 0
+
+
+#endif /* _NGX_ATOMIC_H_INCLUDED_ */
diff --git a/src/os/win32/ngx_os.h b/src/os/win32/ngx_os.h
index aa66e70..84b81a1 100644
--- a/src/os/win32/ngx_os.h
+++ b/src/os/win32/ngx_os.h
@@ -44,6 +44,7 @@
 
 
 extern ngx_os_io_t  ngx_os_io;
+extern int          ngx_ncpu;
 extern int          ngx_max_sockets;
 extern int          ngx_inherited_nonblocking;
 extern int          ngx_win32_version;
diff --git a/src/os/win32/ngx_process.h b/src/os/win32/ngx_process.h
index c858768..2866c44 100644
--- a/src/os/win32/ngx_process.h
+++ b/src/os/win32/ngx_process.h
@@ -23,6 +23,9 @@
 
 ngx_pid_t ngx_execute(ngx_cycle_t *cycle, ngx_exec_ctx_t *ctx);
 
+#define ngx_sched_yeld()  Sleep(0)
+
+
 
 extern ngx_pid_t     ngx_pid;
 
diff --git a/src/os/win32/ngx_win32_init.c b/src/os/win32/ngx_win32_init.c
index 7a25b28..7d9d433 100644
--- a/src/os/win32/ngx_win32_init.c
+++ b/src/os/win32/ngx_win32_init.c
@@ -4,6 +4,7 @@
 
 
 int  ngx_win32_version;
+int  ngx_ncpu;
 int  ngx_max_sockets;
 int  ngx_inherited_nonblocking = 1;
 
@@ -124,6 +125,7 @@
 
     GetSystemInfo(&si);
     ngx_pagesize = si.dwPageSize;
+    ngx_ncpu = si.dwNumberOfProcessors;
 
 
     /* init Winsock */