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authorad <ad@NetBSD.org>2007-08-04 13:37:48 +0000
committerad <ad@NetBSD.org>2007-08-04 13:37:48 +0000
commit50fa8db4e44b07accbfd5f2821987476be3bf05c (patch)
tree04cfc58059fb658923f9a7b24583dd0b3e4437d1 /lib/libpthread/sem.c
parentb108f67c054e0f87f9b653c4d194652a4bfc40cc (diff)
Some significant performance improvements, and a fix for a race with pthread
detach/join. - Make mutex acquire spin for a short time, as done with spinlocks. - Make the number of spins controllable with the env var PTHREAD_NSPINS. - Reduce the amount of time that libpthread internal spinlocks are held. - Rely more on the barrier effects of park/unpark to avoid taking spinlocks. - Simplify the locking around pthreads and the global queues. - Align per-thread sync data on a 128 byte boundary. - Offset thread stacks by a small amount to try and reduce cache thrash.
Diffstat (limited to 'lib/libpthread/sem.c')
-rw-r--r--lib/libpthread/sem.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/lib/libpthread/sem.c b/lib/libpthread/sem.c
index 44fe2940102..b659cf33719 100644
--- a/lib/libpthread/sem.c
+++ b/lib/libpthread/sem.c
@@ -1,4 +1,4 @@
-/* $NetBSD: sem.c,v 1.14 2007/03/24 18:52:00 ad Exp $ */
+/* $NetBSD: sem.c,v 1.15 2007/08/04 13:37:50 ad Exp $ */
/*-
* Copyright (c) 2003, 2006, 2007 The NetBSD Foundation, Inc.
@@ -66,7 +66,7 @@
*/
#include <sys/cdefs.h>
-__RCSID("$NetBSD: sem.c,v 1.14 2007/03/24 18:52:00 ad Exp $");
+__RCSID("$NetBSD: sem.c,v 1.15 2007/08/04 13:37:50 ad Exp $");
#include <sys/types.h>
#include <sys/ksem.h>
@@ -92,7 +92,7 @@ struct _sem_st {
/* Protects data below. */
pthread_spin_t usem_interlock;
- struct pthread_queue_t usem_waiters;
+ pthread_queue_t usem_waiters;
unsigned int usem_count;
};
@@ -287,7 +287,7 @@ sem_wait(sem_t *sem)
{
pthread_t self;
extern int pthread__started;
- struct pthread_queue_t *queue;
+ pthread_queue_t *queue;
#ifdef ERRORCHECK
if (sem == NULL || *sem == NULL || (*sem)->usem_magic != USEM_MAGIC) {
@@ -333,8 +333,10 @@ sem_wait(sem_t *sem)
PTQ_INSERT_TAIL(queue, self, pt_sleep);
self->pt_sleeponq = 1;
self->pt_sleepobj = queue,
+ pthread_spinunlock(self, &(*sem)->usem_interlock);
(void)pthread__park(self, &(*sem)->usem_interlock,
queue, NULL, 1, queue);
+ pthread_spinlock(self, &(*sem)->usem_interlock);
}
(*sem)->usem_count--;
pthread_spinunlock(self, &(*sem)->usem_interlock);