Messages in this thread | | | Date | Tue, 4 Apr 2023 11:53:08 +0200 | Subject | Re: rq lock contention due to commit af7f588d8f73 | From | "Linux regression tracking #adding (Thorsten Leemhuis)" <> |
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[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 27.03.23 10:05, Aaron Lu wrote: > > I was doing some optimization work[1] for kernel scheduler using a > database workload: sysbench+postgres and before I submit my work, I > rebased my patch on top of latest v6.3-rc kernels to see if everything > still works expected and then I found rq's lock became very heavily > contended as compared to v6.2 based kernels. > > Using the above mentioned workload, before commit af7f588d8f73("sched: > Introduce per-memory-map concurrency ID"), the profile looked like: > > 7.30% 0.71% [kernel.vmlinux] [k] __schedule > 0.03% 0.03% [kernel.vmlinux] [k] native_queued_spin_lock_slowpath > > After that commit: > > 49.01% 0.87% [kernel.vmlinux] [k] __schedule > 43.20% 43.18% [kernel.vmlinux] [k] native_queued_spin_lock_slowpath >
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 af7f588d8f73 #regzbot monitor https://lore.kernel.org/lkml/20230403181342.210896-1-mathieu.desnoyers@efficios.com/ #regzbot monitor https://lore.kernel.org/all/20230330230911.228720-1-mathieu.desnoyers@efficios.com/ #regzbot title sched: PostgreSQL performance regression introduced by mm_cid #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.
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