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The g_up and g_down threads use a local 'mymutex' mutex to allow WITNESS

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to warn about attempts to sleep in the I/O path.  This change pushes the
definition and use of 'mymutex' behind #ifdef WITNESS to avoid the cost
in non-debugging cases.  This results in a clear .22% performance win for
512 byte and 1k I/O tests on my SMP test box.  Not much, but every bit
counts.
This commit is contained in:
rwatson 2004-06-26 23:27:42 +00:00
parent 4c4f36d309
commit ddb1bad6a3
1 changed files with 16 additions and 0 deletions
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16
sys/geom/geom_io.c
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@ -315,10 +315,12 @@ g_io_schedule_down(struct thread *tp __unused)
struct bio *bp;
off_t excess;
int error;
#ifdef WITNESS
struct mtx mymutex;
bzero(&mymutex, sizeof mymutex);
mtx_init(&mymutex, "g_xdown", NULL, MTX_DEF);
#endif
for(;;) {
g_bioq_lock(&g_bio_run_down);
@ -357,9 +359,13 @@ g_io_schedule_down(struct thread *tp __unused)
default:
break;
}
#ifdef WITNESS
mtx_lock(&mymutex);
#endif
bp->bio_to->geom->start(bp);
#ifdef WITNESS
mtx_unlock(&mymutex);
#endif
}
}
@ -384,26 +390,36 @@ void
g_io_schedule_up(struct thread *tp __unused)
{
struct bio *bp;
#ifdef WITNESS
struct mtx mymutex;
bzero(&mymutex, sizeof mymutex);
mtx_init(&mymutex, "g_xup", NULL, MTX_DEF);
#endif
for(;;) {
g_bioq_lock(&g_bio_run_up);
bp = g_bioq_first(&g_bio_run_task);
if (bp != NULL) {
g_bioq_unlock(&g_bio_run_up);
#ifdef WITNESS
mtx_lock(&mymutex);
#endif
bp->bio_task(bp->bio_task_arg);
#ifdef WITNESS
mtx_unlock(&mymutex);
#endif
continue;
}
bp = g_bioq_first(&g_bio_run_up);
if (bp != NULL) {
g_bioq_unlock(&g_bio_run_up);
#ifdef WITNESS
mtx_lock(&mymutex);
#endif
biodone(bp);
#ifdef WITNESS
mtx_unlock(&mymutex);
#endif
continue;
}
msleep(&g_wait_up, &g_bio_run_up.bio_queue_lock,