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authorRich Felker <dalias@aerifal.cx>2014-10-20 00:22:51 -0400
committerRich Felker <dalias@aerifal.cx>2014-10-20 00:22:51 -0400
commitdc95322e18615392eea69de355edd735a15a8f36 (patch)
tree3386437650008764e8b9a9a61c389d067a6bd3dd /src
parent60a4783ed4bd0496f7eb31f9b7eb2ad10df46677 (diff)
downloadmusl-dc95322e18615392eea69de355edd735a15a8f36.tar.gz
manually "shrink wrap" fast path in pthread_once
this change is a workaround for the inability of current compilers to perform "shrink wrapping" optimizations. in casual testing, it roughly doubled the performance of pthread_once when called on an already-finished once control object.
Diffstat (limited to 'src')
-rw-r--r--src/thread/pthread_once.c20
1 files changed, 12 insertions, 8 deletions
diff --git a/src/thread/pthread_once.c b/src/thread/pthread_once.c
index 7c47385c..df655ef9 100644
--- a/src/thread/pthread_once.c
+++ b/src/thread/pthread_once.c
@@ -8,15 +8,8 @@ static void undo(void *control)
__wake(control, -1, 1);
}
-int __pthread_once(pthread_once_t *control, void (*init)(void))
+int __pthread_once_full(pthread_once_t *control, void (*init)(void))
{
- /* Return immediately if init finished before, but ensure that
- * effects of the init routine are visible to the caller. */
- if (*control == 2) {
- a_barrier();
- return 0;
- }
-
/* Try to enter initializing state. Four possibilities:
* 0 - we're the first or the other cancelled; run init
* 1 - another thread is running init; wait
@@ -43,4 +36,15 @@ int __pthread_once(pthread_once_t *control, void (*init)(void))
}
}
+int __pthread_once(pthread_once_t *control, void (*init)(void))
+{
+ /* Return immediately if init finished before, but ensure that
+ * effects of the init routine are visible to the caller. */
+ if (*control == 2) {
+ a_barrier();
+ return 0;
+ }
+ return __pthread_once_full(control, init);
+}
+
weak_alias(__pthread_once, pthread_once);