* config/linux/wait.h (do_spin): New inline, largely copied

	from do_wait, just don't do futex_wait here, instead return true if
	it should be done.
	(do_wait): Implement using do_spin.
	* config/linux/mutex.h (gomp_mutex_lock_slow): Add an int argument
	to prototype.
	(gomp_mutex_lock): Use __sync_val_compare_and_swap instead of
	__sync_bool_compare_and_swap, pass the oldval to
	gomp_mutex_lock_slow.
	* config/linux/mutex.c (gomp_mutex_lock_slow): Add oldval argument.
	If all mutex contenders are just spinning and not sleeping, don't
	change state to 2 unnecessarily.  Optimize the loop when state has
	already become 2 to use just one atomic operation per loop instead
	of two.
	* config/linux/ia64/mutex.h (gomp_mutex_lock_slow): Add an int argument
	to prototype.
	(gomp_mutex_lock): Use __sync_val_compare_and_swap instead of
	__sync_bool_compare_and_swap, pass the oldval to
	gomp_mutex_lock_slow.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@176326 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 5 insertions, 4 deletions

diff --git a/libgomp/config/linux/ia64/mutex.h b/libgomp/config/linux/ia64/mutex.h
index 6e294059b23..8a67673df40 100644
--- a/libgomp/config/linux/ia64/mutex.h
+++ b/libgomp/config/linux/ia64/mutex.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2005, 2008, 2009 Free Software Foundation, Inc.
+/* Copyright (C) 2005, 2008, 2009, 2011 Free Software Foundation, Inc.
    Contributed by Richard Henderson <rth@redhat.com>.
 
    This file is part of the GNU OpenMP Library (libgomp).
@@ -38,11 +38,12 @@ static inline void gomp_mutex_init (gomp_mutex_t *mutex)
   *mutex = 0;
 }
 
-extern void gomp_mutex_lock_slow (gomp_mutex_t *mutex);
+extern void gomp_mutex_lock_slow (gomp_mutex_t *mutex, int);
 static inline void gomp_mutex_lock (gomp_mutex_t *mutex)
 {
-  if (!__sync_bool_compare_and_swap (mutex, 0, 1))
-    gomp_mutex_lock_slow (mutex);
+  int oldval = __sync_val_compare_and_swap (mutex, 0, 1);
+  if (__builtin_expect (oldval, 0))
+    gomp_mutex_lock_slow (mutex, oldval);
 }
 
 extern void gomp_mutex_unlock_slow (gomp_mutex_t *mutex);