diff options
| author | jhb <jhb@FreeBSD.org> | 2002-06-04 21:53:48 +0000 |
|---|---|---|
| committer | jhb <jhb@FreeBSD.org> | 2002-06-04 21:53:48 +0000 |
| commit | 408adb728768f69cb8966c1191020d6ea7e66be5 (patch) | |
| tree | 74dd2af195979cba72051f324486634264a843a6 /sys/kern/kern_mutex.c | |
| parent | 1ba6786436ce1fc3d10f82452a167a784b696702 (diff) | |
| download | FreeBSD-src-408adb728768f69cb8966c1191020d6ea7e66be5.zip FreeBSD-src-408adb728768f69cb8966c1191020d6ea7e66be5.tar.gz | |
Optimize the adaptive mutex spin a bit. Use a simple while loop with
simple reads (and on IA32, a "pause" instruction for each interation of the
loop) to spin until either the mutex owner field changes, or the lock owner
stops executing.
Suggested by: tanimura
Tested on: i386
Diffstat (limited to 'sys/kern/kern_mutex.c')
| -rw-r--r-- | sys/kern/kern_mutex.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c index f9b7413..d0fc8c9 100644 --- a/sys/kern/kern_mutex.c +++ b/sys/kern/kern_mutex.c @@ -536,9 +536,12 @@ _mtx_lock_sleep(struct mtx *m, int opts, const char *file, int line) owner = (struct thread *)(v & MTX_FLAGMASK); if (m != &Giant && thread_runnable(owner)) { mtx_unlock_spin(&sched_lock); + while (mtx_owner(m) == owner && + thread_runnable(owner)) { #ifdef __i386__ - ia32_pause(); + ia32_pause(); #endif + } continue; } #endif /* SMP && ADAPTIVE_MUTEXES */ |
