From: Christoph Hellwig <hch@infradead.org>
To: Song Liu <song@kernel.org>
Cc: linux-block@vger.kernel.org, linux-raid@vger.kernel.org,
axboe@kernel.dk, stable@vger.kernel.org,
Larkin Lowrey <llowrey@nuclearwinter.com>,
Wilson Jonathan <i400sjon@gmail.com>,
Roger Heflin <rogerheflin@gmail.com>
Subject: Re: [PATCH] block: check more requests for multiple_queues in blk_attempt_plug_merge
Date: Wed, 9 Mar 2022 22:48:12 -0800 [thread overview]
Message-ID: <YimfLJoWLKnnhLfR@infradead.org> (raw)
In-Reply-To: <20220309064209.4169303-1-song@kernel.org>
On Tue, Mar 08, 2022 at 10:42:09PM -0800, Song Liu wrote:
> RAID arrays check/repair operations benefit a lot from merging requests.
> If we only check the previous entry for merge attempt, many merge will be
> missed. As a result, significant regression is observed for RAID check
> and repair.
>
> Fix this by checking more than just the previous entry when
> plug->multiple_queues == true.
But this also means really significant CPU overhead for all other
workloads.
>
> This improves the check/repair speed of a 20-HDD raid6 from 19 MB/s to
> 103 MB/s.
What driver uses multiple queues for HDDs?
Can you explain the workload submitted by a md a bit better? I wonder
if we can easily do the right thing straight in the md driver.
next prev parent reply other threads:[~2022-03-10 6:48 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-09 6:42 [PATCH] block: check more requests for multiple_queues in blk_attempt_plug_merge Song Liu
2022-03-10 6:48 ` Christoph Hellwig [this message]
2022-03-10 7:23 ` Song Liu
2022-03-10 22:10 ` Song Liu
2022-03-10 22:12 ` Song Liu
2022-03-10 22:15 ` Jens Axboe
2022-03-10 22:37 ` Song Liu
2022-03-10 23:02 ` Jens Axboe
2022-03-10 23:33 ` Song Liu
2022-03-11 0:07 ` Jens Axboe
2022-03-11 0:31 ` Song Liu
2022-03-11 0:36 ` Jens Axboe
2022-03-11 0:38 ` Jens Axboe
2022-03-11 1:14 ` Ming Lei
2022-03-11 1:21 ` Jens Axboe
2022-03-11 1:32 ` Ming Lei
2022-03-11 1:35 ` Jens Axboe
2022-03-11 8:09 ` Wols Lists
2022-03-11 14:16 ` Jens Axboe
2022-03-11 16:59 ` Song Liu
2022-03-11 21:41 ` Paul Menzel
2022-03-11 22:40 ` Song Liu
2022-03-11 11:30 ` Wilson Jonathan
2022-03-11 15:58 ` Wols Lists
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