linux-kernel - Re: [PATCH v1 2/2] perf script: Fix for `perf script +F metric` with leader sampling

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Message-ID: <Zp_Ozo_Iyu1sgL9h@tassilo>
Date: Tue, 23 Jul 2024 08:39:58 -0700
From: Andi Kleen <ak@...ux.intel.com>
To: James Clark <james.clark@...aro.org>
Cc: Ian Rogers <irogers@...gle.com>, Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Kan Liang <kan.liang@...ux.intel.com>,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
	Athira Rajeev <atrajeev@...ux.vnet.ibm.com>
Subject: Re: [PATCH v1 2/2] perf script: Fix for `perf script +F metric` with
 leader sampling

> Yeah I suppose it's strictly better now without the segfault. Could you pull
> in the test and update it to add -a? At least then that behavior will be
> locked down and we can extend it later without -a.

Ian's patch really implements completely new functionality (supporting
metrics over multiple groups). It isn't a regression fix, but completely
redesigns the old "single group" feature.

> I also tested Andi's V5 and still got the segfault.

Yes the earlier versions worked, but they broke perf stat report.
I think the right short term fix is to use V3 or so, but with a
check that perf stat report isn't used.

Then perhaps the new functionality of multiple groups can be considered
over it.

-Andi