Commit 3c764b7a authored Dec 04, 2009 by Shaohua Li Committed by Jens Axboe Dec 04, 2009

cfq-iosched: make nonrot check logic consistent

cfq_arm_slice_timer() has logic to disable idle window for SSD device. The same
thing should be done at cfq_select_queue() too, otherwise we will still see
idle window. This makes the nonrot check logic consistent in cfq.
Tests in a intel SSD with low_latency knob close, below patch can triple disk
thoughput for muti-thread sequential read.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

parent 237e5bc4

block/cfq-iosched.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1796,7 +1796,8 @@ static bool cfq_should_idle(struct cfq_data cfqd, struct cfq_queue cfqq)
		return false;

		/* We do for queues that were marked with idle window flag. */
		if (cfq_cfqq_idle_window(cfqq))
		if (cfq_cfqq_idle_window(cfqq) &&
		!(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag))
		return true;

		/*