diff options
| author | Yonghong Song <yhs@fb.com> | 2020-01-16 09:40:04 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-01-16 13:28:57 -0800 |
| commit | 35697c12d7ffd31a56d3c9604066a166b75d0169 (patch) | |
| tree | 959a081af0c6533335d84f7615b1911fd1911f09 | |
| parent | 858e284f0ec18bff2620d9a6afe764dc683f8ba1 (diff) | |
selftests/bpf: Fix test_progs send_signal flakiness with nmi mode
Alexei observed that test_progs send_signal may fail if run
with command line "./test_progs" and the tests will pass
if just run "./test_progs -n 40".
I observed similar issue with nmi subtest failure
and added a delay 100 us in Commit ab8b7f0cb358
("tools/bpf: Add self tests for bpf_send_signal_thread()")
and the problem is gone for me. But the issue still exists
in Alexei's testing environment.
The current code uses sample_freq = 50 (50 events/second), which
may not be enough. But if the sample_freq value is larger than
sysctl kernel/perf_event_max_sample_rate, the perf_event_open
syscall will fail.
This patch changed nmi perf testing to use sample_period = 1,
which means trying to sampling every event. This seems fixing
the issue.
Fixes: ab8b7f0cb358 ("tools/bpf: Add self tests for bpf_send_signal_thread()")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200116174004.1522812-1-yhs@fb.com
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/send_signal.c | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c index d4cedd86c424..504abb7bfb95 100644 --- a/tools/testing/selftests/bpf/prog_tests/send_signal.c +++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c @@ -76,9 +76,6 @@ static void test_send_signal_common(struct perf_event_attr *attr, if (CHECK(!skel, "skel_open_and_load", "skeleton open_and_load failed\n")) goto skel_open_load_failure; - /* add a delay for child thread to ramp up */ - usleep(100); - if (!attr) { err = test_send_signal_kern__attach(skel); if (CHECK(err, "skel_attach", "skeleton attach failed\n")) { @@ -155,8 +152,7 @@ static void test_send_signal_perf(bool signal_thread) static void test_send_signal_nmi(bool signal_thread) { struct perf_event_attr attr = { - .sample_freq = 50, - .freq = 1, + .sample_period = 1, .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CPU_CYCLES, }; |