From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6AB61C001DC for ; Sun, 23 Jul 2023 12:11:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229597AbjGWMLg (ORCPT ); Sun, 23 Jul 2023 08:11:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229491AbjGWMLf (ORCPT ); Sun, 23 Jul 2023 08:11:35 -0400 Received: from wp530.webpack.hosteurope.de (wp530.webpack.hosteurope.de [80.237.130.52]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 57F9B1BF; Sun, 23 Jul 2023 05:11:31 -0700 (PDT) Received: from [2a02:8108:8980:2478:8cde:aa2c:f324:937e]; authenticated by wp530.webpack.hosteurope.de running ExIM with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) id 1qNXvt-0006o4-EM; Sun, 23 Jul 2023 14:11:29 +0200 Message-ID: <03b96f88-559c-454a-702c-90b0ca50b3b6@leemhuis.info> Date: Sun, 23 Jul 2023 14:11:28 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH 6.4 800/800] io_uring: Use io_schedule* in cqring wait Content-Language: en-US, de-DE To: Oleksandr Natalenko , stable@vger.kernel.org Cc: Greg Kroah-Hartman , Pavel Begunkov , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, Andres Freund , Jens Axboe , Linux kernel regressions list References: <20230716194949.099592437@linuxfoundation.org> <20230716195007.731909670@linuxfoundation.org> <12251678.O9o76ZdvQC@natalenko.name> From: "Linux regression tracking #adding (Thorsten Leemhuis)" Reply-To: Linux regressions mailing list In-Reply-To: <12251678.O9o76ZdvQC@natalenko.name> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-bounce-key: webpack.hosteurope.de;regressions@leemhuis.info;1690114291;ae7eaa41; X-HE-SMSGID: 1qNXvt-0006o4-EM Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org [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 >> >> 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.