Index: thread/thr_init.c
===================================================================
RCS file: /home/ncvs/src/lib/libthr/thread/thr_init.c,v
retrieving revision 1.46
diff -u -r1.46 thr_init.c
--- thread/thr_init.c	9 May 2007 08:39:33 -0000	1.46
+++ thread/thr_init.c	17 Oct 2007 08:40:21 -0000
@@ -103,6 +103,8 @@
 size_t		_thr_stack_default = THR_STACK_DEFAULT;
 size_t		_thr_stack_initial = THR_STACK_INITIAL;
 int		_thr_page_size;
+int		_thr_max_spins = 1000;
+int		_thr_min_spins = 200;
 int		_gc_count;
 struct umutex	_mutex_static_lock = DEFAULT_UMUTEX;
 struct umutex	_cond_static_lock = DEFAULT_UMUTEX;
@@ -423,6 +425,7 @@
 {
 	size_t len;
 	int mib[2];
+	char *spin_env;
 
 	_thr_umutex_init(&_mutex_static_lock);
 	_thr_umutex_init(&_cond_static_lock);
@@ -452,7 +455,9 @@
 		_thr_guard_default = _thr_page_size;
 		_pthread_attr_default.guardsize_attr = _thr_guard_default;
 		_pthread_attr_default.stacksize_attr = _thr_stack_default;
-
+		spin_env = getenv("LIBPTHREAD_MUTEX_MAXSPIN");
+		if (spin_env)
+			_thr_max_spins = atoi(spin_env);
 		TAILQ_INIT(&_thr_atfork_list);
 	}
 	init_once = 1;
Index: thread/thr_mutex.c
===================================================================
RCS file: /home/ncvs/src/lib/libthr/thread/thr_mutex.c,v
retrieving revision 1.54
diff -u -r1.54 thr_mutex.c
--- thread/thr_mutex.c	9 May 2007 08:39:33 -0000	1.54
+++ thread/thr_mutex.c	17 Oct 2007 08:40:21 -0000
@@ -121,6 +121,7 @@
 		pmutex->m_flags |= MUTEX_FLAGS_PRIVATE;
 	pmutex->m_count = 0;
 	pmutex->m_refcount = 0;
+	pmutex->m_spins = _thr_min_spins;
 	MUTEX_INIT_LINK(pmutex);
 	switch(attr->m_protocol) {
 	case PTHREAD_PRIO_INHERIT:
@@ -271,6 +272,16 @@
 	return (ret);
 }
 
+
+#define ENQUEUE_MUTEX(curthread, m)  					\
+		m->m_owner = curthread;					\
+		/* Add to the list of owned mutexes: */			\
+		MUTEX_ASSERT_NOT_OWNED(m);				\
+		if ((m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)	\
+			TAILQ_INSERT_TAIL(&curthread->mutexq, m, m_qe);	\
+		else							\
+			TAILQ_INSERT_TAIL(&curthread->pp_mutexq, m, m_qe)
+
 static int
 mutex_trylock_common(struct pthread *curthread, pthread_mutex_t *mutex)
 {
@@ -282,13 +293,7 @@
 	m = *mutex;
 	ret = _thr_umutex_trylock(&m->m_lock, id);
 	if (ret == 0) {
-		m->m_owner = curthread;
-		/* Add to the list of owned mutexes. */
-		MUTEX_ASSERT_NOT_OWNED(m);
-		if ((m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)
-			TAILQ_INSERT_TAIL(&curthread->mutexq, m, m_qe);
-		else
-			TAILQ_INSERT_TAIL(&curthread->pp_mutexq, m, m_qe);
+		ENQUEUE_MUTEX(curthread, m);
 	} else if (m->m_owner == curthread) {
 		ret = mutex_self_trylock(m);
 	} /* else {} */
@@ -340,22 +345,44 @@
 	struct	pthread_mutex *m;
 	uint32_t	id;
 	int	ret;
+	int	count;
+	int	temp;
 
 	id = TID(curthread);
 	m = *mutex;
 	ret = _thr_umutex_trylock2(&m->m_lock, id);
 	if (ret == 0) {
-		m->m_owner = curthread;
-		/* Add to the list of owned mutexes: */
-		MUTEX_ASSERT_NOT_OWNED(m);
-		if ((m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)
-			TAILQ_INSERT_TAIL(&curthread->mutexq, m, m_qe);
-		else
-			TAILQ_INSERT_TAIL(&curthread->pp_mutexq, m, m_qe);
+		ENQUEUE_MUTEX(curthread, m);
 	} else if (m->m_owner == curthread) {
 		ret = mutex_self_lock(m, abstime);
 	} else {
 		if (abstime == NULL) {
+			if (!(m->m_lock.m_flags & UMUTEX_PRIO_PROTECT)) {
+				temp  = 0;
+				count = m->m_spins;
+				while (m->m_lock.m_owner != UMUTEX_UNOWNED) {
+					if (temp == count)
+						break;
+					temp++;
+					CPU_SPINWAIT;
+				}
+				if (temp != count) {
+					ret = _thr_umutex_trylock2(&m->m_lock, id);
+					if (ret == 0) {
+						ENQUEUE_MUTEX(curthread, m);
+						m->m_spins -= temp/8;
+						if (m->m_spins < _thr_min_spins)
+							m->m_spins = _thr_min_spins;
+						return (ret);
+					}
+				}
+				m->m_spins += temp/8;
+				if (m->m_spins > _thr_max_spins) {
+					m->m_spins -= _thr_max_spins;
+					if (m->m_spins < _thr_min_spins)
+						m->m_spins = _thr_min_spins;
+				}
+			}
 			ret = __thr_umutex_lock(&m->m_lock);
 		} else if (__predict_false(
 			   abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
@@ -372,16 +399,8 @@
 			if (ret == EINTR)
 				ret = ETIMEDOUT;
 		}
-		if (ret == 0) {
-			m->m_owner = curthread;
-			/* Add to the list of owned mutexes: */
-			MUTEX_ASSERT_NOT_OWNED(m);
-			if ((m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)
-				TAILQ_INSERT_TAIL(&curthread->mutexq, m, m_qe);
-			else
-				TAILQ_INSERT_TAIL(&curthread->pp_mutexq, m,
-					m_qe);
-		}
+		if (ret == 0)
+			ENQUEUE_MUTEX(curthread, m);
 	}
 	return (ret);
 }
Index: thread/thr_private.h
===================================================================
RCS file: /home/ncvs/src/lib/libthr/thread/thr_private.h,v
retrieving revision 1.78
diff -u -r1.78 thr_private.h
--- thread/thr_private.h	7 Aug 2007 04:50:14 -0000	1.78
+++ thread/thr_private.h	17 Oct 2007 08:40:21 -0000
@@ -119,6 +119,7 @@
 	int				m_flags;
 	int				m_count;
 	int				m_refcount;
+	int				m_spins;
 	/*
 	 * Link for all mutexes a thread currently owns.
 	 */
@@ -584,6 +585,8 @@
 extern size_t	_thr_stack_initial __hidden;
 extern int	_thr_page_size __hidden;
 extern int	_thr_adaptive_spin __hidden;
+extern int	_thr_max_spins __hidden;
+extern int	_thr_min_spins __hidden;
 /* Garbage thread count. */
 extern int	_gc_count __hidden;