From: Dave Chinner <david@fromorbit.com>
To: Anton Gavriliuk <antosha20xx@gmail.com>
Cc: Laurence Oberman <loberman@redhat.com>,
linux-nvme@lists.infradead.org, linux-xfs@vger.kernel.org,
linux-block@vger.kernel.org
Subject: Re: Sequential read from NVMe/XFS twice slower on Fedora 42 than on Rocky 9.5
Date: Wed, 7 May 2025 07:46:01 +1000 [thread overview]
Message-ID: <aBqDGY1i3RePyzaB@dread.disaster.area> (raw)
In-Reply-To: <CAAiJnjo87CEeFrkHbXtQM-=+K9M8uEpythLthWTwM_-i4HMA_Q@mail.gmail.com>
On Tue, May 06, 2025 at 02:03:37PM +0300, Anton Gavriliuk wrote:
> > So is this MD chunk size related? i.e. what is the chunk size
> > the MD device? Is it smaller than the IO size (256kB) or larger?
> > Does the regression go away if the chunk size matches the IO size,
> > or if the IO size vs chunk size relationship is reversed?
>
> According to the output below, the chunk size is 512K,
Ok.
`iostat -dxm 5` output during the fio run on both kernels will give
us some indication of the differences in IO patterns, queue depths,
etc.
Silly question: if you use DM to create the same RAID 0 array
with a dm table such as:
0 75011629056 striped 12 1024 /dev/nvme7n1 0 /dev/nvme0n1 0 .... /dev/nvme12n1 0
to create a similar 38TB raid 0 array, do you see the same perf
degradation?
-Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2025-05-06 21:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAAiJnjoo0--yp47UKZhbu8sNSZN6DZ-QzmZBMmtr1oC=fOOgAQ@mail.gmail.com>
[not found] ` <aBaVsli2AKbIa4We@dread.disaster.area>
[not found] ` <CAAiJnjor+=Zn62n09f-aJw2amX2wxQOb-2TB3rea9wDCU7ONoA@mail.gmail.com>
2025-05-04 21:50 ` Sequential read from NVMe/XFS twice slower on Fedora 42 than on Rocky 9.5 Dave Chinner
2025-05-05 12:29 ` Laurence Oberman
2025-05-05 13:21 ` Laurence Oberman
2025-05-05 17:39 ` Laurence Oberman
2025-05-22 15:07 ` Laurence Oberman
2025-05-23 9:39 ` Anton Gavriliuk
2025-05-05 22:56 ` Dave Chinner
2025-05-06 11:03 ` Anton Gavriliuk
2025-05-06 21:46 ` Dave Chinner [this message]
2025-05-07 12:26 ` Anton Gavriliuk
2025-05-07 21:59 ` Dave Chinner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=aBqDGY1i3RePyzaB@dread.disaster.area \
--to=david@fromorbit.com \
--cc=antosha20xx@gmail.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-nvme@lists.infradead.org \
--cc=linux-xfs@vger.kernel.org \
--cc=loberman@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).