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Commit 63de428b authored by Aaron Carroll's avatar Aaron Carroll Committed by Jens Axboe
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deadline-iosched: allow non-sequential batching 



Deadline currently only batches sector-contiguous requests, so except
for a few circumstances (e.g. requests in a single direction), it is
essentially first come first served.  This is bad for throughput, so
change it to CSCAN, which means requests in a batch do not need to be
sequential and are issued in increasing sector order.

Signed-off-by: default avatarAaron Carroll <aaronc@gelato.unsw.edu.au>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 766ca442

block/deadline-iosched.c

+3 −11
Original line number Diff line number Diff line
@@ -258,17 +258,9 @@ static int deadline_dispatch_requests(struct request_queue *q, int force) 
	else

		rq = dd->next_rq[READ];



	if (rq) {

		/* we have a "next request" */

		

		if (dd->last_sector != rq->sector)

			/* end the batch on a non sequential request */

			dd->batching += dd->fifo_batch;

		

		if (dd->batching < dd->fifo_batch)

			/* we are still entitled to batch */

	if (rq && dd->batching < dd->fifo_batch)

		/* we have a next request are still entitled to batch */

		goto dispatch_request;

	}



	/*

	 * at this point we are not running a batch. select the appropriate