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From: Miroslav Cimerman <mc@raidlab.org>
To: song@kernel.org, yukuai@fygo.io
Cc: antosha20xx@gmail.com, magiclinan@didiglobal.com,
	xiao@kernel.org, neil@brown.name, tj@kernel.org,
	linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] md/raid5: fix write stalls when a write is queued during a drain
Date: Sun, 15 Nov 2026 13:55:15 +0100	[thread overview]
Message-ID: <20261115125515.56112-1-mc@raidlab.org> (raw)
In-Reply-To: <20261114224636.34362-1-mc@raidlab.org>

Anton Gavriliuk tested the patch on the same machine as the raid6
store patch: HPE DL345 Gen11, AMD EPYC 9455, 6x PCIe 5.0 NVMe, RAID-6
4+2, chunk 512K, no bitmap, rmw_level=2, v7.4-rc2 with and without
the patch, fio 4k randwrite, O_DIRECT, io_uring, 60 s, 2 runs per
kernel. Slowest write and IOPS:

  md defaults, 1 job x QD64:
    without  max 59.3 s / 45.1 s    128k / 124k IOPS
    with     max 2.9 ms / 2.9 ms    129k / 126k IOPS

  group_thread_cnt=8, stripe_cache_size=32768, 16 jobs x QD64:
    without  max 56.4 s / 57.5 s    472k / 474k IOPS
    with     max 9.2 ms / 11.2 ms   483k / 479k IOPS

Without the patch the slowest write of every run took 45-59 s of the
60 s. With the patch a few milliseconds. IOPS stayed the same or went
up a bit.

Miroslav

      reply	other threads:[~2026-11-15 12:55 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-14 22:46 Miroslav Cimerman
2026-11-15 12:55 ` Miroslav Cimerman [this message]

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