[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@xxxxxxxxxxx> >> >> 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.
