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| author | davidxu <davidxu@FreeBSD.org> | 2012-05-03 09:17:31 +0000 |
|---|---|---|
| committer | davidxu <davidxu@FreeBSD.org> | 2012-05-03 09:17:31 +0000 |
| commit | 520dba8f2897914f2ceccc1e916009a3b00c3ad9 (patch) | |
| tree | ed9550b886413ddf07f7d057d29b37d1ce5bce06 /lib/libthr | |
| parent | 46b1e41aff0313c3b831f1bdfbc076495fd68fbc (diff) | |
| download | FreeBSD-src-520dba8f2897914f2ceccc1e916009a3b00c3ad9.zip FreeBSD-src-520dba8f2897914f2ceccc1e916009a3b00c3ad9.tar.gz | |
MFp4:
Enqueue thread in LIFO, this can cause starvation, but it gives better
performance. Use _thr_queuefifo to control the frequency of FIFO vs LIFO,
you can use environment string LIBPTHREAD_QUEUE_FIFO to configure the
variable.
Diffstat (limited to 'lib/libthr')
| -rw-r--r-- | lib/libthr/thread/thr_init.c | 4 | ||||
| -rw-r--r-- | lib/libthr/thread/thr_private.h | 1 | ||||
| -rw-r--r-- | lib/libthr/thread/thr_sleepq.c | 6 |
3 files changed, 10 insertions, 1 deletions
diff --git a/lib/libthr/thread/thr_init.c b/lib/libthr/thread/thr_init.c index 86abad8..e1e304a 100644 --- a/lib/libthr/thread/thr_init.c +++ b/lib/libthr/thread/thr_init.c @@ -112,6 +112,7 @@ size_t _thr_stack_initial = THR_STACK_INITIAL; int _thr_page_size; int _thr_spinloops; int _thr_yieldloops; +int _thr_queuefifo = 4; int _gc_count; struct umutex _mutex_static_lock = DEFAULT_UMUTEX; struct umutex _cond_static_lock = DEFAULT_UMUTEX; @@ -470,6 +471,9 @@ init_private(void) env = getenv("LIBPTHREAD_YIELDLOOPS"); if (env) _thr_yieldloops = atoi(env); + env = getenv("LIBPTHREAD_QUEUE_FIFO"); + if (env) + _thr_queuefifo = atoi(env); TAILQ_INIT(&_thr_atfork_list); } init_once = 1; diff --git a/lib/libthr/thread/thr_private.h b/lib/libthr/thread/thr_private.h index 4469f6b..5224c7c 100644 --- a/lib/libthr/thread/thr_private.h +++ b/lib/libthr/thread/thr_private.h @@ -710,6 +710,7 @@ extern size_t _thr_stack_initial __hidden; extern int _thr_page_size __hidden; extern int _thr_spinloops __hidden; extern int _thr_yieldloops __hidden; +extern int _thr_queuefifo __hidden; /* Garbage thread count. */ extern int _gc_count __hidden; diff --git a/lib/libthr/thread/thr_sleepq.c b/lib/libthr/thread/thr_sleepq.c index 8549a87..40553cb 100644 --- a/lib/libthr/thread/thr_sleepq.c +++ b/lib/libthr/thread/thr_sleepq.c @@ -39,6 +39,7 @@ struct sleepqueue_chain { struct umutex sc_lock; + int sc_enqcnt; LIST_HEAD(, sleepqueue) sc_queues; int sc_type; }; @@ -124,7 +125,10 @@ _sleepq_add(void *wchan, struct pthread *td) } td->sleepqueue = NULL; td->wchan = wchan; - TAILQ_INSERT_TAIL(&sq->sq_blocked, td, wle); + if (((++sc->sc_enqcnt << _thr_queuefifo) & 0xff) != 0) + TAILQ_INSERT_HEAD(&sq->sq_blocked, td, wle); + else + TAILQ_INSERT_TAIL(&sq->sq_blocked, td, wle); } int |
