Commit 9ede209e authored by Jens Axboe's avatar Jens Axboe Committed by Jens Axboe
Browse files

cfq-iosched: improve continue or break logic in cfq_dispatch 



This improves performance considerably for sync requests when you
have command queuing enabled.

Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 28f95cbc

block/cfq-iosched.c

+8 −8
Original line number Diff line number Diff line
@@ -1057,6 +1057,14 @@ cfq_dispatch_requests(request_queue_t *q, int force) 
		if (prev_cfqq == cfqq)

			break;



		/*

		 * So we have dispatched before in this round, if the

		 * next queue has idling enabled (must be sync), don't

		 * allow it service until the previous have continued.

		 */

		if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq))

			break;



		cfq_clear_cfqq_must_dispatch(cfqq);

		cfq_clear_cfqq_wait_request(cfqq);

		del_timer(&cfqd->idle_slice_timer);
@@ -1066,14 +1074,6 @@ cfq_dispatch_requests(request_queue_t *q, int force) 
			max_dispatch = 1;



		dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);



		/*

		 * If the dispatch cfqq has idling enabled and is still

		 * the active queue, break out.

		 */

		if (cfq_cfqq_idle_window(cfqq) && cfqd->active_queue)

			break;



		prev_cfqq = cfqq;

	}