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authorJens Axboe <jens.axboe@oracle.com>2008-10-20 15:44:28 +0200
committerJens Axboe <jens.axboe@oracle.com>2008-12-29 08:29:51 +0100
commit30e0dc28bff9dc456cdfc2aae4aca78b8b1a1cec (patch)
treecb72eba9e27bf893928189c832d29e97bbe132ad /block
parent31dcfab0ae6eb0340d456931df4d478e17efc65d (diff)
downloadlinux-2.6.34-ux500-30e0dc28bff9dc456cdfc2aae4aca78b8b1a1cec.tar.gz
cfq-iosched: remove limit of dispatch depth of max 4 times quantum
This basically limits the hardware queue depth to 4*quantum at any point in time, which is 16 with the default settings. As CFQ uses other means to shrink the hardware queue when necessary in the first place, there's really no need for this extra heuristic. Additionally, it ends up hurting performance in some cases. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
-rw-r--r--block/cfq-iosched.c8
1 files changed, 2 insertions, 6 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index adaf93a9d19..ee8a90c7c46 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1136,12 +1136,8 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
if (cfq_class_idle(cfqq))
max_dispatch = 1;
- if (cfqq->dispatched >= max_dispatch) {
- if (cfqd->busy_queues > 1)
- break;
- if (cfqq->dispatched >= 4 * max_dispatch)
- break;
- }
+ if (cfqq->dispatched >= max_dispatch && cfqd->busy_queues > 1)
+ break;
if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq))
break;