linux-kernel - Re: [PING PATCH v3] perf test: Allow tolerance for leader sampling test

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Message-ID: <aBIeFio2nkbzFj0b@x1>
Date: Wed, 30 Apr 2025 09:56:54 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Thomas Richter <tmricht@...ux.ibm.com>
Cc: linux-kernel@...r.kernel.org, linux-s390@...r.kernel.org,
	linux-perf-users@...r.kernel.org, namhyung@...nel.org,
	ctshao@...gle.com, irogers@...gle.com, agordeev@...ux.ibm.com,
	gor@...ux.ibm.com, sumanthk@...ux.ibm.com, hca@...ux.ibm.com
Subject: Re: [PING PATCH v3] perf test: Allow tolerance for leader sampling
 test

On Tue, Apr 22, 2025 at 01:06:43PM +0200, Thomas Richter wrote:
> V3: Added check for missing samples as suggested by Chun-Tse.
> V2: Changed bc invocation to return 0 on success and 1 on error.
 
> There is a known issue that the leader sampling is inconsistent, since
> throttle only affect leader, not the slave. The detail is in [1]. To
> maintain test coverage, this patch sets a tolerance rate of 80% to
> accommodate the throttled samples and prevent test failures due to
> throttling.
 
> [1] lore.kernel.org/20250328182752.769662-1-ctshao@...gle.com
 
> Signed-off-by: Chun-Tse Shao <ctshao@...gle.com>
> Suggested-by: Ian Rogers <irogers@...gle.com>
> Suggested-by: Thomas Richter <tmricht@...ux.ibm.com>
> Tested-by: Thomas Richter <tmricht@...ux.ibm.com>
> Signed-off-by: Thomas Richter <tmricht@...ux.ibm.com>

This doesn't apply to perf-tools-next:

⬢ [acme@...lbx perf-tools-next]$        git am ./v3_20250422_tmricht_perf_test_allow_tolerance_for_leader_sampling_test.mbx
Applying: perf test: Allow tolerance for leader sampling test
error: patch failed: tools/perf/tests/shell/record.sh:238
error: tools/perf/tests/shell/record.sh: patch does not apply
Patch failed at 0001 perf test: Allow tolerance for leader sampling test
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"
⬢ [acme@...lbx perf-tools-next]$

Are you proposing this for perf-tools, i.e. for this release cycles?

Namhyung, what do you think?

I think it is not applying in perf-tools-next due to this patch that
isn't in perf-tools:

⬢ [acme@...lbx perf-tools-next]$ git log --oneline -5 perf-tools-next/perf-tools-next tools/perf/tests/shell/record.sh
be8aefad33760dd8 perf tests record: Cleanup improvements <<<<<<<<<<<<<<<<<<<<<<<<<<<<
90d97674d4ad0166 perf test: Use cycles event in perf record test for leader_sampling
859199431d768091 perf test: Fix perf record test for precise_max
180fd0c1eac7cd8c perf tests: Make leader sampling test work without branch event
2532be3d219d8819 perf test: Tag parallel failing shell tests with "(exclusive)"
⬢ [acme@...lbx perf-tools-next]$

⬢ [acme@...lbx perf-tools-next]$ git log --oneline -5 perf-tools/perf-tools tools/perf/tests/shell/record.sh
90d97674d4ad0166 perf test: Use cycles event in perf record test for leader_sampling
859199431d768091 perf test: Fix perf record test for precise_max
180fd0c1eac7cd8c perf tests: Make leader sampling test work without branch event
2532be3d219d8819 perf test: Tag parallel failing shell tests with "(exclusive)"
36fae9f93e5f00eb perf test: Add precise_max subtest to the perf record shell test
⬢ [acme@...lbx perf-tools-next]$

- Arnaldo