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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/thread/thr_sleepq.c | |
| 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/thread/thr_sleepq.c')
| -rw-r--r-- | lib/libthr/thread/thr_sleepq.c | 6 |
1 files changed, 5 insertions, 1 deletions
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 |
