From: Yu Kuai <yukuai1@huaweicloud.com>
To: Tom Crane <T.Crane@rhul.ac.uk>, linux-raid@vger.kernel.org
Cc: "yukuai (C)" <yukuai3@huawei.com>
Subject: Re: RAID performance limited by single kernel thread mdX_raid6 ?
Date: Sat, 20 Apr 2024 09:59:32 +0800 [thread overview]
Message-ID: <ef6626c8-a0ad-7eef-d1cd-ccd3fdfbabf8@huaweicloud.com> (raw)
In-Reply-To: <d26a7e97-b120-45ee-9063-e156d79b3e37@rhul.ac.uk>
Hi,
在 2024/04/13 1:35, Tom Crane 写道:
> We have a newly built RAID6 array built using the LVM subsystem. It
> comprises 12-off 1TB NVME drives and 12 stripes to match the number of
> drives.
>
> The performance seems to be limited by the single [mdX_raid6] kernel
> thread which 'top' shows is maxed out at 100% CPU (on a single core)
> when performance testing the array.
No, IO fast path is not involved with the daemon thread. Daemon thread
is used to handle IO errer, sync IO, update sb, handle spares...
Thanks,
Kuai
>
> The kernel is a fairly old one (Redhat's 3.10.0-1160.114.2.el7.x86_64)
> on a Centos7 system. A cursory googling of the topic does not suggest
> that later kernels (e.g. Redhat's 5.14.0-362.18.1.el9_3.x86_64 should we
> upgrade the system to an EL9 distro) have multi-threaded this... Can
> anyone comment ?
>
>
> Many thanks
>
> Tom Crane.
>
> ps. I'm not subscribed to this ML so please CC me when replying.
>
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prev parent reply other threads:[~2024-04-20 1:59 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-12 17:35 RAID performance limited by single kernel thread mdX_raid6 ? Tom Crane
2024-04-20 1:59 ` Yu Kuai [this message]
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