From: Bart Van Assche <bvanassche@acm.org>
To: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Jaegeuk Kim <jaegeuk@kernel.org>,
Damien Le Moal <damien.lemoal@wdc.com>,
Niklas Cassel <Niklas.Cassel@wdc.com>,
Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCH v2 4/4] block/mq-deadline: Prioritize high-priority requests
Date: Mon, 28 Mar 2022 21:49:45 -0700 [thread overview]
Message-ID: <3d4b4c68-0c9d-b4bb-3ce1-14ee5417ba19@acm.org> (raw)
In-Reply-To: <844fdda0-37d2-4335-d755-1348482201a9@acm.org>
On 3/27/22 19:20, Bart Van Assche wrote:
> Thanks, this helps a lot. can_queue = 1 as I was suspecting. In a quick
> test I noticed that I/O is about 10x slower for queue depth 1 and the
> v5.17 mq-deadline scheduler. I will take a closer look at this tomorrow.
(replying to my own email)
Please take a look at the two new tests in
https://github.com/osandov/blktests/pull/87. The results of that test for
kernel v5.13 show that enabling an I/O scheduler speeds up the I/O workload
except when using BFQ (times are in centiseconds):
# cat /home/bart/software/blktests/results/nodev/block/032.full
bfq: 465 vs 452: pass
kyber: 243 vs 452: pass
mq-deadline: 230 vs 452: pass
The results for kernel v5.16 shows that enabling an I/O scheduler slows down
the I/O workload up to 2.2x:
# cat /home/bart/software/blktests/results/nodev/block/032.full
bfq: 920 vs 419: fail
kyber: 732 vs 419: fail
mq-deadline: 751 vs 419: fail
In other words, this is not an mq-deadline issue.
Bart.
next prev parent reply other threads:[~2022-03-29 4:49 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-27 22:03 [PATCH v2 0/4] Restore I/O priority support in the mq-deadline scheduler Bart Van Assche
2021-09-27 22:03 ` [PATCH v2 1/4] block/mq-deadline: Improve request accounting further Bart Van Assche
2021-09-28 5:45 ` Hannes Reinecke
2021-09-27 22:03 ` [PATCH v2 2/4] block/mq-deadline: Add an invariant check Bart Van Assche
2021-09-28 5:47 ` Hannes Reinecke
2021-09-27 22:03 ` [PATCH v2 3/4] block/mq-deadline: Stop using per-CPU counters Bart Van Assche
2021-09-28 5:51 ` Hannes Reinecke
2021-09-28 17:35 ` Bart Van Assche
2021-09-27 22:03 ` [PATCH v2 4/4] block/mq-deadline: Prioritize high-priority requests Bart Van Assche
2021-09-27 22:53 ` Damien Le Moal
2021-09-27 23:12 ` Bart Van Assche
2021-09-28 5:53 ` Hannes Reinecke
2021-09-28 10:36 ` Niklas Cassel
2022-03-25 12:33 ` Oleksij Rempel
2022-03-25 13:07 ` Oleksij Rempel
2022-03-25 17:05 ` Bart Van Assche
2022-03-26 8:57 ` Oleksij Rempel
2022-03-28 2:20 ` Bart Van Assche
2022-03-28 22:24 ` Bart Van Assche
2022-03-29 4:49 ` Bart Van Assche [this message]
2021-09-27 23:14 ` [PATCH v2 0/4] Restore I/O priority support in the mq-deadline scheduler Jens Axboe
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