Re: [PATCH v4 10/13] perf tests: Speed up off-cpu profiling tests

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The commit message inaccurately states the new total test sleep overhead is 0.3s (yielding a ~2.7s speedup), but the actual new sleep overhead is 0.5s due to `test_offcpu_basic` using `sleep 0.3`. Additionally, the commit silently lowers `--percent-limit` from 90 to 70 without documentation.
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commit 9b1dfc522cff7ce2083aaf529f3e6b60de599b14
Author: Ian Rogers <irogers@google.com>

perf tests: Speed up off-cpu profiling tests

The commit scales down the off-cpu threshold tests to reduce test sleep
overhead from 3.0s down to a stated 0.3s.

> This reduces raw test sleep overhead from 3.0s down to 0.3s, yielding a
> ~2.7 second speedup for this test.

[Severity: Medium]
Does this commit message accurately reflect the new total sleep overhead?

Looking at the test script changes, test_offcpu_basic() uses sleep 0.3, while
test_offcpu_above_thresh() and test_offcpu_below_thresh() each use sleep 0.1.
This adds up to 0.5s of total sleep overhead, rather than the 0.3s mentioned
here.

> diff --git a/tools/perf/tests/shell/record_offcpu.sh b/tools/perf/tests/shell/record_offcpu.sh
> index 860a2d6f4b75f..ee095df47358b 100755
> --- a/tools/perf/tests/shell/record_offcpu.sh
> +++ b/tools/perf/tests/shell/record_offcpu.sh
> @@ -57,7 +57,7 @@ test_offcpu_basic() {
>      err=1
>      return
>    fi
> -  if ! perf report -i ${perfdata} -q --percent-limit=90 | grep -E -q sleep
> +  if ! perf report -i ${perfdata} -q --percent-limit=70 | grep -E -q sleep
>    then
>      echo "Basic off-cpu test [Failed missing output]"
>      err=1

[Severity: Medium]
Was it intentional to lower the percent-limit from 90 to 70?

This modifies the test logic for test_offcpu_basic(), but the change doesn't
appear to be documented in the commit message.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260623012758.2291858-1-irogers@google.com?part=10