diff options
| author | Tim Chase <[email protected]> | 2016-10-10 17:19:14 -0500 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2016-10-10 15:19:14 -0700 |
| commit | d33931a83a33db4034186dfda6dcdd294ace2c75 (patch) | |
| tree | ed3f60d617440d0e4012eaffc739c00a81534039 /module/zfs/spa.c | |
| parent | 57f16600b981f38585a956ae674488640424f711 (diff) | |
Write issue taskq shouldn't be dynamic
This is as much an upstream compatibility as it's a bit of a performance
gain.
The illumos taskq implemention doesn't allow a TASKQ_THREADS_CPU_PCT type
to be dynamic and in fact enforces as much with an ASSERT.
As to performance, if this taskq is dynamic, it can cause excessive
contention on tq_lock as the threads are created and destroyed because it
can see bursts of many thousands of tasks in a short time, particularly
in heavy high-concurrency zvol write workloads.
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tim Chase <[email protected]>
Closes #5236
Diffstat (limited to 'module/zfs/spa.c')
| -rw-r--r-- | module/zfs/spa.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/module/zfs/spa.c b/module/zfs/spa.c index 0a480d3ec..bd1134e8f 100644 --- a/module/zfs/spa.c +++ b/module/zfs/spa.c @@ -862,7 +862,7 @@ spa_taskqs_init(spa_t *spa, zio_type_t t, zio_taskq_type_t q) uint_t count = ztip->zti_count; spa_taskqs_t *tqs = &spa->spa_zio_taskq[t][q]; char name[32]; - uint_t i, flags = TASKQ_DYNAMIC; + uint_t i, flags = 0; boolean_t batch = B_FALSE; if (mode == ZTI_MODE_NULL) { @@ -880,6 +880,7 @@ spa_taskqs_init(spa_t *spa, zio_type_t t, zio_taskq_type_t q) case ZTI_MODE_FIXED: ASSERT3U(value, >=, 1); value = MAX(value, 1); + flags |= TASKQ_DYNAMIC; break; case ZTI_MODE_BATCH: |