linux-kernel - [PATCH v1 0/3] Parse event sort/regroup fixes

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Message-Id: <20230719001836.198363-1-irogers@google.com>
Date:   Tue, 18 Jul 2023 17:18:33 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Andi Kleen <ak@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Zhengjun Xing <zhengjun.xing@...ux.intel.com>,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v1 0/3] Parse event sort/regroup fixes

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/

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