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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 15:24:37 -0700	[thread overview]
Message-ID: <7b75c6bf-b446-2883-a571-d6ec3e99d575@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.

An update: I can reproduce the slowness with (a) the patch at the start of
this thread reverted and (b) both the BFQ and the Kyber I/O schedulers. So
it seems like a regression has been introduced related to handling of queue
depth 1. I will try to bisect this.

Bart.

  reply	other threads:[~2022-03-28 22:24 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 [this message]
2022-03-29  4:49           ` Bart Van Assche
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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