Author: davidxu
Date: Thu May 3 09:17:31 2012
New Revision: 234947
URL: http://svn.freebsd.org/changeset/base/234947
Log:
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.
Modified:
head/lib/libthr/thread/thr_init.c
head/lib/libthr/thread/thr_private.h
head/lib/libthr/thread/thr_sleepq.c
Modified: head/lib/libthr/thread/thr_init.c
==============================================================================
--- head/lib/libthr/thread/thr_init.c Thu May 3 08:56:43 2012
(r234946)
+++ head/lib/libthr/thread/thr_init.c Thu May 3 09:17:31 2012
(r234947)
@@ -112,6 +112,7 @@ size_t _thr_stack_initial = THR_STACK_I
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;
Modified: head/lib/libthr/thread/thr_private.h
==============================================================================
--- head/lib/libthr/thread/thr_private.h Thu May 3 08:56:43 2012
(r234946)
+++ head/lib/libthr/thread/thr_private.h Thu May 3 09:17:31 2012
(r234947)
@@ -710,6 +710,7 @@ extern size_t _thr_stack_initial __hidde
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;
Modified: head/lib/libthr/thread/thr_sleepq.c
==============================================================================
--- head/lib/libthr/thread/thr_sleepq.c Thu May 3 08:56:43 2012
(r234946)
+++ head/lib/libthr/thread/thr_sleepq.c Thu May 3 09:17:31 2012
(r234947)
@@ -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->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
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