Messages in this thread | | | From | Vincent Guittot <> | Date | Wed, 12 Jan 2022 14:17:51 +0100 | Subject | Re: [PATCH v3 0/4] sched/pelt: Relax the sync of *_sum with *_avg |
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On Wed, 12 Jan 2022 at 12:24, Sachin Sant <sachinp@linux.vnet.ibm.com> wrote: > > > > On 11-Jan-2022, at 7:16 PM, Vincent Guittot <vincent.guittot@linaro.org> wrote: > > > > Rick reported performance regressions in bugzilla because of cpu > > frequency being lower than before: > > https://bugzilla.kernel.org/show_bug.cgi?id=215045 > > > > He bisected the problem to: > > commit 1c35b07e6d39 ("sched/fair: Ensure _sum and _avg values stay consistent") > > > > More details are available in commit message of patch 1. > > > > This patchset reverts the commit above and adds several checks when > > propagating the changes in the hierarchy to make sure that we still have > > coherent util_avg and util_sum. > > > > Dietmar found a simple way to reproduce the WARN fixed by > > commit 1c35b07e6d39 ("sched/fair: Ensure _sum and _avg values stay consistent") > > by looping on hackbench in several different sched group levels. > > > > This patchset as run on the reproducer with success but it probably needs > > more tests by people who faced the WARN before. > > > > I ran scheduler regression tests(including cfg_bandwidth) from LTP > for about 6 hours. I did not observe any (new or previously reported) > kernel warn messages. > > Based on this test result for ppc64le > Tested-by: Sachin Sant <sachinp@linux.ibm.com>
Thanks
> > -Sachin
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