Check environment variable PTHREAD_ADAPTIVE_SPIN, if it is set, use

it as a default spin cycle count.

5 files changed, 8 insertions, 1 deletions

diff --git a/lib/libthr/thread/thr_init.c b/lib/libthr/thread/thr_init.c
index 981941b..31c361c 100644
--- a/lib/libthr/thread/thr_init.c
+++ b/lib/libthr/thread/thr_init.c
@@ -66,6 +66,7 @@ pthreadlist 	_thread_gc_list = TAILQ_HEAD_INITIALIZER(_thread_gc_list);
 int		_thread_active_threads = 1;
 atfork_head	_thr_atfork_list = TAILQ_HEAD_INITIALIZER(_thr_atfork_list);
 struct umutex	_thr_atfork_lock = DEFAULT_UMUTEX;
+int		_thr_adaptive_spin = 0;
 
 struct pthread_prio	_thr_priorities[3] = {
 	{RTP_PRIO_MIN,  RTP_PRIO_MAX, 0}, /* FIFO */
@@ -423,6 +424,7 @@ init_private(void)
 {
 	size_t len;
 	int mib[2];
+	char *p;
 
 	_thr_umutex_init(&_mutex_static_lock);
 	_thr_umutex_init(&_cond_static_lock);
@@ -454,6 +456,8 @@ init_private(void)
 		_pthread_attr_default.stacksize_attr = _thr_stack_default;
 
 		TAILQ_INIT(&_thr_atfork_list);
+		if ((p = getenv("LIBPTHREAD_ADAPTIVE_SPIN")) != NULL)
+			_thr_adaptive_spin = atoi(p);
 	}
 	init_once = 1;
 }
diff --git a/lib/libthr/thread/thr_mutex.c b/lib/libthr/thread/thr_mutex.c
index aae27aa..17e067a 100644
--- a/lib/libthr/thread/thr_mutex.c
+++ b/lib/libthr/thread/thr_mutex.c
@@ -136,6 +136,7 @@ mutex_init(pthread_mutex_t *mutex,
 		pmutex->m_lock.m_owner = UMUTEX_UNOWNED;
 		pmutex->m_lock.m_flags = 0;
 	}
+	pmutex->m_lock.m_spincount = _thr_adaptive_spin;
 	*mutex = pmutex;
 	return (0);
 }
diff --git a/lib/libthr/thread/thr_private.h b/lib/libthr/thread/thr_private.h
index d3a179c..eb2632d 100644
--- a/lib/libthr/thread/thr_private.h
+++ b/lib/libthr/thread/thr_private.h
@@ -583,6 +583,7 @@ extern size_t	_thr_guard_default __hidden;
 extern size_t	_thr_stack_default __hidden;
 extern size_t	_thr_stack_initial __hidden;
 extern int	_thr_page_size __hidden;
+extern int	_thr_adaptive_spin __hidden;
 /* Garbage thread count. */
 extern int	_gc_count __hidden;
 
diff --git a/lib/libthr/thread/thr_umtx.c b/lib/libthr/thread/thr_umtx.c
index 0a5ee6a..1aa89ca 100644
--- a/lib/libthr/thread/thr_umtx.c
+++ b/lib/libthr/thread/thr_umtx.c
@@ -36,6 +36,7 @@ _thr_umutex_init(struct umutex *mtx)
 	static struct umutex default_mtx = DEFAULT_UMUTEX;
 
 	*mtx = default_mtx;
+	mtx->m_spincount = _thr_adaptive_spin;
 }
 
 int
diff --git a/lib/libthr/thread/thr_umtx.h b/lib/libthr/thread/thr_umtx.h
index 8696320..1a60c1a 100644
--- a/lib/libthr/thread/thr_umtx.h
+++ b/lib/libthr/thread/thr_umtx.h
@@ -32,7 +32,7 @@
 #include <strings.h>
 #include <sys/umtx.h>
 
-#define DEFAULT_UMUTEX	{0, 0, {0, 0}, {0, 0, 0, 0}}
+#define DEFAULT_UMUTEX	{0}
 
 typedef long umtx_t;