Messages in this thread | | | Date | Thu, 28 Sep 2023 09:24:55 -0700 | Subject | Re: [PATCH v4 0/2] Avoid spurious freezer wakeups | From | Elliot Berman <> |
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Hi Peter,
On 9/26/2023 1:02 PM, Peter Zijlstra wrote: > On Tue, Sep 26, 2023 at 04:17:33PM +0000, Carlos Llamas wrote: >> On Fri, Sep 08, 2023 at 03:49:14PM -0700, Elliot Berman wrote: >>> After commit f5d39b020809 ("freezer,sched: Rewrite core freezer logic"), >>> tasks that transition directly from TASK_FREEZABLE to TASK_FROZEN are >>> always woken up on the thaw path. Prior to that commit, tasks could ask >>> freezer to consider them "frozen enough" via freezer_do_not_count(). The >>> commit replaced freezer_do_not_count() with a TASK_FREEZABLE state which >>> allows freezer to immediately mark the task as TASK_FROZEN without >>> waking up the task. This is efficient for the suspend path, but on the >>> thaw path, the task is always woken up even if the task didn't need to >>> wake up and goes back to its TASK_(UN)INTERRUPTIBLE state. Although >>> these tasks are capable of handling of the wakeup, we can observe a >>> power/perf impact from the extra wakeup. >> >> This issue is hurting the performance of our stable 6.1 releases. Does >> it make sense to backport these patches into stable branches once they >> land in mainline? I would assume we want to fix the perf regression >> there too? > > Note that these patches are in tip/sched/core, slated for the next merge > window.
Can the changes be scheduled for the next 6.6-rc? I'd like to get the changes backported to stable sooner since we observed the regression on real systems.
Thanks, Elliot
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