Re: [PATCH v1 0/3] Parse event sort/regroup fixes

From: Arnaldo Carvalho de Melo
Date: Wed Jul 19 2023 - 10:50:22 EST


Em Tue, Jul 18, 2023 at 05:18:33PM -0700, Ian Rogers escreveu:
> Patch 1, fix:
> perf stat -e cycles,slots,topdown-fe-bound
> so that cycles isn't made a group leader (failure caused by PMUs
> matching). Previously this event list would fail so not necessarily a
> regression over previous perf release.
>
> Patch 2, when regrouping events the leader needs to be updated due to
> sorting. This fix causes larger event groups that then regress at
> least the tigerlake metric test as the kernel PMU driver fails to
> break the weak groups. This is a fix for a bug but the consequence of
> fixing the bug is to make a passing test fail due to the kernel PMU
> driver.
>
> Patch 3, don't alter the list position of events without a group if
> they don't need forcing into a group. Analysis showed this was the
> cause of the issue reported by Andi Kleen:
> https://lore.kernel.org/linux-perf-users/ZLBgbHkbrfGygM%2Fu@tassilo/

Andi,

Can you please check these patches and provide a Tested-by?

Thanks,

- Arnaldo

> Due to the test regression in patch 2, follow up patches may be
> necessary for Icelake+ Intel vendor metrics to add METRIC_NO_GROUP to
> avoid the kernel PMU driver issue.
>
> Ian Rogers (3):
> perf parse-events: Extra care around force grouped events
> perf parse-events: When fixing group leaders always set the leader
> perf parse-events: Only move force grouped evsels when sorting
>
> tools/perf/util/parse-events.c | 58 +++++++++++++++++++++-------------
> 1 file changed, 36 insertions(+), 22 deletions(-)
>
> --
> 2.41.0.487.g6d72f3e995-goog