selftests/bpf: bpf_cookie: Make perf_event subtest trigger reliably

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The perf_event subtest relies on SW_CPU_CLOCK sampling to trigger the BPF
program, but the current CPU burn loop can be too short on slower systems
and may fail to generate any overflow sample. This leaves pe_res unchanged
and makes the test flaky.

Make burn_cpu() take a loop count and use a longer burn only for the
perf_event subtest. Also scope perf_event_open() to the current task to
avoid wasting samples on unrelated activity.

Signed-off-by: Sun Jian <sun.jian.kdev@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20260228074555.122950-3-sun.jian.kdev@gmail.com

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Sun Jian 2026-02-28 15:45:55 +08:00 • committed by Andrii Nakryiko

parent 74d3305e62

commit 7f20d371fd

1 changed files with 11 additions and 8 deletions

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tools/testing/selftests/bpf/prog_tests/bpf_cookie.c

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