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authorJens Axboe <axboe@suse.de>2006-06-01 04:12:26 -0400
committerJens Axboe <axboe@suse.de>2006-06-01 04:12:26 -0400
commit25776e3594f841b7fae7b33ebecf009a0a55bed1 (patch)
tree689dcf37ba781ad627ae01be4fcb6f5414f67c1b
parent12e9fddd6eb827937fcaac8ac7712c7303898b1f (diff)
[PATCH] cfq-iosched: Detect hardware queueing
If the hardware is doing real queueing, decide that it's worthless to idle the hardware. It does reasonable simultaneous io in that case anyways, and the idling hurts some work loads. Signed-off-by: Jens Axboe <axboe@suse.de>
-rw-r--r--block/cfq-iosched.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 93ba54605eda..5d2047b93eb5 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -133,6 +133,7 @@ struct cfq_data {
133 mempool_t *crq_pool; 133 mempool_t *crq_pool;
134 134
135 int rq_in_driver; 135 int rq_in_driver;
136 int hw_tag;
136 137
137 /* 138 /*
138 * schedule slice state info 139 * schedule slice state info
@@ -664,6 +665,15 @@ static void cfq_activate_request(request_queue_t *q, struct request *rq)
664 struct cfq_data *cfqd = q->elevator->elevator_data; 665 struct cfq_data *cfqd = q->elevator->elevator_data;
665 666
666 cfqd->rq_in_driver++; 667 cfqd->rq_in_driver++;
668
669 /*
670 * If the depth is larger 1, it really could be queueing. But lets
671 * make the mark a little higher - idling could still be good for
672 * low queueing, and a low queueing number could also just indicate
673 * a SCSI mid layer like behaviour where limit+1 is often seen.
674 */
675 if (!cfqd->hw_tag && cfqd->rq_in_driver > 4)
676 cfqd->hw_tag = 1;
667} 677}
668 678
669static void cfq_deactivate_request(request_queue_t *q, struct request *rq) 679static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
@@ -1465,7 +1475,8 @@ retry:
1465 * set ->slice_left to allow preemption for a new process 1475 * set ->slice_left to allow preemption for a new process
1466 */ 1476 */
1467 cfqq->slice_left = 2 * cfqd->cfq_slice_idle; 1477 cfqq->slice_left = 2 * cfqd->cfq_slice_idle;
1468 cfq_mark_cfqq_idle_window(cfqq); 1478 if (!cfqd->hw_tag)
1479 cfq_mark_cfqq_idle_window(cfqq);
1469 cfq_mark_cfqq_prio_changed(cfqq); 1480 cfq_mark_cfqq_prio_changed(cfqq);
1470 cfq_init_prio_data(cfqq); 1481 cfq_init_prio_data(cfqq);
1471 } 1482 }
@@ -1656,7 +1667,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
1656{ 1667{
1657 int enable_idle = cfq_cfqq_idle_window(cfqq); 1668 int enable_idle = cfq_cfqq_idle_window(cfqq);
1658 1669
1659 if (!cic->ioc->task || !cfqd->cfq_slice_idle) 1670 if (!cic->ioc->task || !cfqd->cfq_slice_idle || cfqd->hw_tag)
1660 enable_idle = 0; 1671 enable_idle = 0;
1661 else if (sample_valid(cic->ttime_samples)) { 1672 else if (sample_valid(cic->ttime_samples)) {
1662 if (cic->ttime_mean > cfqd->cfq_slice_idle) 1673 if (cic->ttime_mean > cfqd->cfq_slice_idle)