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selftests/bpf: Use PERF_COUNT_HW_CPU_CYCLES event for get_branch_snapshot

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perf_event with type=PERF_TYPE_RAW and config=0x1b00 turned out to be not
reliable in ensuring LBR is active. Thus, test_progs:get_branch_snapshot is
not reliable in some systems. Replace it with PERF_COUNT_HW_CPU_CYCLES
event, which gives more consistent results.

Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230407190130.2093736-1-song@kernel.org
This commit is contained in:
Song Liu 2023-04-07 12:01:30 -07:00 committed by Andrii Nakryiko
parent f3f2134977
commit 3ebf5212bf
1 changed files with 2 additions and 2 deletions
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tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c
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@ -37,8 +37,8 @@ static int create_perf_events(void)
/* create perf event */
attr.size = sizeof(attr);
attr.type = PERF_TYPE_RAW;
attr.config = 0x1b00;
attr.type = PERF_TYPE_HARDWARE;
attr.config = PERF_COUNT_HW_CPU_CYCLES;
attr.sample_type = PERF_SAMPLE_BRANCH_STACK;
attr.branch_sample_type = PERF_SAMPLE_BRANCH_KERNEL |
PERF_SAMPLE_BRANCH_USER | PERF_SAMPLE_BRANCH_ANY;