linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Linux regression tracking #adding (Thorsten Leemhuis)"  <regressions@leemhuis.info>
To: Oleksandr Natalenko <oleksandr@natalenko.name>, stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Pavel Begunkov <asml.silence@gmail.com>,
	io-uring@vger.kernel.org, linux-kernel@vger.kernel.org,
	Andres Freund <andres@anarazel.de>, Jens Axboe <axboe@kernel.dk>,
	Linux kernel regressions list <regressions@lists.linux.dev>
Subject: Re: [PATCH 6.4 800/800] io_uring: Use io_schedule* in cqring wait
Date: Sun, 23 Jul 2023 14:11:28 +0200	[thread overview]
Message-ID: <03b96f88-559c-454a-702c-90b0ca50b3b6@leemhuis.info> (raw)
In-Reply-To: <12251678.O9o76ZdvQC@natalenko.name>

[CCing the regression list, as it should be in the loop for regressions:
https://docs.kernel.org/admin-guide/reporting-regressions.html]

[TLDR: I'm adding this report to the list of tracked Linux kernel
regressions; the text you find below is based on a few templates
paragraphs you might have encountered already in similar form.
See link in footer if these mails annoy you.]

On 23.07.23 11:39, Oleksandr Natalenko wrote:
> On neděle 16. července 2023 21:50:53 CEST Greg Kroah-Hartman wrote:
>> From: Andres Freund <andres@anarazel.de>
>>
>> commit 8a796565cec3601071cbbd27d6304e202019d014 upstream.
>>
>> I observed poor performance of io_uring compared to synchronous IO. That
>> turns out to be caused by deeper CPU idle states entered with io_uring,
>> due to io_uring using plain schedule(), whereas synchronous IO uses
>> io_schedule().
>>
>> The losses due to this are substantial. On my cascade lake workstation,
>> t/io_uring from the fio repository e.g. yields regressions between 20%
>> and 40% with the following command:
>> ./t/io_uring -r 5 -X0 -d 1 -s 1 -c 1 -p 0 -S$use_sync -R 0 /mnt/t2/fio/write.0.0
>>
> 
> Reportedly, this caused a regression as reported in [1] [2] [3]. Not only v6.4.4 is affected, v6.1.39 is affected too.
> 
> Reverting this commit fixes the issue.
> 
> Please check.
> 
> Thanks.
> 
> [1] https://bbs.archlinux.org/viewtopic.php?id=287343
> [2] https://bugzilla.kernel.org/show_bug.cgi?id=217700
> [3] https://bugzilla.kernel.org/show_bug.cgi?id=217699

Thanks for the report. To be sure the issue doesn't fall through the
cracks unnoticed, I'm adding it to regzbot, the Linux kernel regression
tracking bot:

#regzbot introduced 8a796565cec360107 ^
https://bbs.archlinux.org/viewtopic.php?id=287343
https://bugzilla.kernel.org/show_bug.cgi?id=217700
https://bugzilla.kernel.org/show_bug.cgi?id=217699
#regzbot title block: io_uring: high iowait rates and stalls
#regzbot ignore-activity

This isn't a regression? This issue or a fix for it are already
discussed somewhere else? It was fixed already? You want to clarify when
the regression started to happen? Or point out I got the title or
something else totally wrong? Then just reply and tell me -- ideally
while also telling regzbot about it, as explained by the page listed in
the footer of this mail.

Developers: When fixing the issue, remember to add 'Link:' tags pointing
to the report (the parent of this mail). See page linked in footer for
details.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
That page also explains what to do if mails like this annoy you.

  parent reply	other threads:[~2023-07-23 12:11 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-16 19:37 [PATCH 6.4 000/800] 6.4.4-rc1 review Greg Kroah-Hartman
2023-07-16 19:39 ` [PATCH 6.4 119/800] sctp: add bpf_bypass_getsockopt proto callback Greg Kroah-Hartman
2023-07-16 19:50 ` [PATCH 6.4 800/800] io_uring: Use io_schedule* in cqring wait Greg Kroah-Hartman
2023-07-23  9:39   ` Oleksandr Natalenko
2023-07-23 10:50     ` Greg Kroah-Hartman
2023-07-23 10:55       ` Genes Lists
2023-07-23 10:56       ` Oleksandr Natalenko
2023-07-23 12:11     ` Linux regression tracking #adding (Thorsten Leemhuis) [this message]
2023-07-23 17:35       ` Linux regression tracking #update (Thorsten Leemhuis)
2023-07-23 15:31     ` Jens Axboe
2023-07-23 17:43       ` Genes Lists
2023-07-23 18:06         ` Oleksandr Natalenko
2023-07-23 18:58           ` Andres Freund
2023-07-23 19:44             ` Genes Lists
2023-07-24 15:47           ` Jens Axboe
2023-07-24 18:04             ` Genes Lists
2023-07-17  5:53 ` [PATCH 6.4 000/800] 6.4.4-rc1 review Naresh Kamboju
2023-07-17 18:48   ` Greg Kroah-Hartman
2023-07-17 11:51 ` Ron Economos
2023-07-17 13:37 ` Guenter Roeck
2023-07-17 17:24   ` Greg Kroah-Hartman
2023-07-17 17:32 ` Conor Dooley
2023-07-17 20:46 ` Shuah Khan

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=03b96f88-559c-454a-702c-90b0ca50b3b6@leemhuis.info \
    --to=regressions@leemhuis.info \
    --cc=andres@anarazel.de \
    --cc=asml.silence@gmail.com \
    --cc=axboe@kernel.dk \
    --cc=gregkh@linuxfoundation.org \
    --cc=io-uring@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=oleksandr@natalenko.name \
    --cc=regressions@lists.linux.dev \
    --cc=stable@vger.kernel.org \
    /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).