From d4121376ac7a9c81a696d7558789b2f29ef3574e Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Thu, 21 Oct 2021 13:41:30 +0200 Subject: [PATCH 1/3] selftests/bpf: Fix perf_buffer test on system with offline cpus The perf_buffer fails on system with offline cpus: # test_progs -t perf_buffer test_perf_buffer:PASS:nr_cpus 0 nsec test_perf_buffer:PASS:nr_on_cpus 0 nsec test_perf_buffer:PASS:skel_load 0 nsec test_perf_buffer:PASS:attach_kprobe 0 nsec test_perf_buffer:PASS:perf_buf__new 0 nsec test_perf_buffer:PASS:epoll_fd 0 nsec skipping offline CPU #24 skipping offline CPU #25 skipping offline CPU #26 skipping offline CPU #27 skipping offline CPU #28 skipping offline CPU #29 skipping offline CPU #30 skipping offline CPU #31 test_perf_buffer:PASS:perf_buffer__poll 0 nsec test_perf_buffer:PASS:seen_cpu_cnt 0 nsec test_perf_buffer:FAIL:buf_cnt got 24, expected 32 Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED Changing the test to check online cpus instead of possible. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20211021114132.8196-2-jolsa@kernel.org --- tools/testing/selftests/bpf/prog_tests/perf_buffer.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/perf_buffer.c b/tools/testing/selftests/bpf/prog_tests/perf_buffer.c index 6979aff4aab2..877600392851 100644 --- a/tools/testing/selftests/bpf/prog_tests/perf_buffer.c +++ b/tools/testing/selftests/bpf/prog_tests/perf_buffer.c @@ -107,8 +107,8 @@ void serial_test_perf_buffer(void) "expect %d, seen %d\n", nr_on_cpus, CPU_COUNT(&cpu_seen))) goto out_free_pb; - if (CHECK(perf_buffer__buffer_cnt(pb) != nr_cpus, "buf_cnt", - "got %zu, expected %d\n", perf_buffer__buffer_cnt(pb), nr_cpus)) + if (CHECK(perf_buffer__buffer_cnt(pb) != nr_on_cpus, "buf_cnt", + "got %zu, expected %d\n", perf_buffer__buffer_cnt(pb), nr_on_cpus)) goto out_close; for (i = 0; i < nr_cpus; i++) { From aa274f98b269b2babf37b6308f8a1a009ca4fc41 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Thu, 21 Oct 2021 13:41:31 +0200 Subject: [PATCH 2/3] selftests/bpf: Fix possible/online index mismatch in perf_buffer test The perf_buffer fails on system with offline cpus: # test_progs -t perf_buffer serial_test_perf_buffer:PASS:nr_cpus 0 nsec serial_test_perf_buffer:PASS:nr_on_cpus 0 nsec serial_test_perf_buffer:PASS:skel_load 0 nsec serial_test_perf_buffer:PASS:attach_kprobe 0 nsec serial_test_perf_buffer:PASS:perf_buf__new 0 nsec serial_test_perf_buffer:PASS:epoll_fd 0 nsec skipping offline CPU #4 serial_test_perf_buffer:PASS:perf_buffer__poll 0 nsec serial_test_perf_buffer:PASS:seen_cpu_cnt 0 nsec serial_test_perf_buffer:PASS:buf_cnt 0 nsec ... serial_test_perf_buffer:PASS:fd_check 0 nsec serial_test_perf_buffer:PASS:drain_buf 0 nsec serial_test_perf_buffer:PASS:consume_buf 0 nsec serial_test_perf_buffer:FAIL:cpu_seen cpu 5 not seen #88 perf_buffer:FAIL Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED If the offline cpu is from the middle of the possible set, we get mismatch with possible and online cpu buffers. The perf buffer test calls perf_buffer__consume_buffer for all 'possible' cpus, but the library holds only 'online' cpu buffers and perf_buffer__consume_buffer returns them based on index. Adding extra (online) index to keep track of online buffers, we need the original (possible) index to trigger trace on proper cpu. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20211021114132.8196-3-jolsa@kernel.org --- .../testing/selftests/bpf/prog_tests/perf_buffer.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/perf_buffer.c b/tools/testing/selftests/bpf/prog_tests/perf_buffer.c index 877600392851..0b0cd045979b 100644 --- a/tools/testing/selftests/bpf/prog_tests/perf_buffer.c +++ b/tools/testing/selftests/bpf/prog_tests/perf_buffer.c @@ -45,7 +45,7 @@ int trigger_on_cpu(int cpu) void serial_test_perf_buffer(void) { - int err, on_len, nr_on_cpus = 0, nr_cpus, i; + int err, on_len, nr_on_cpus = 0, nr_cpus, i, j; struct perf_buffer_opts pb_opts = {}; struct test_perf_buffer *skel; cpu_set_t cpu_seen; @@ -111,15 +111,15 @@ void serial_test_perf_buffer(void) "got %zu, expected %d\n", perf_buffer__buffer_cnt(pb), nr_on_cpus)) goto out_close; - for (i = 0; i < nr_cpus; i++) { + for (i = 0, j = 0; i < nr_cpus; i++) { if (i >= on_len || !online[i]) continue; - fd = perf_buffer__buffer_fd(pb, i); + fd = perf_buffer__buffer_fd(pb, j); CHECK(fd < 0 || last_fd == fd, "fd_check", "last fd %d == fd %d\n", last_fd, fd); last_fd = fd; - err = perf_buffer__consume_buffer(pb, i); + err = perf_buffer__consume_buffer(pb, j); if (CHECK(err, "drain_buf", "cpu %d, err %d\n", i, err)) goto out_close; @@ -127,12 +127,13 @@ void serial_test_perf_buffer(void) if (trigger_on_cpu(i)) goto out_close; - err = perf_buffer__consume_buffer(pb, i); - if (CHECK(err, "consume_buf", "cpu %d, err %d\n", i, err)) + err = perf_buffer__consume_buffer(pb, j); + if (CHECK(err, "consume_buf", "cpu %d, err %d\n", j, err)) goto out_close; if (CHECK(!CPU_ISSET(i, &cpu_seen), "cpu_seen", "cpu %d not seen\n", i)) goto out_close; + j++; } out_free_pb: From 99d099757ab487e0d317c69541b47aaae0b6c431 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Thu, 21 Oct 2021 13:41:32 +0200 Subject: [PATCH 3/3] selftests/bpf: Use nanosleep tracepoint in perf buffer test The perf buffer tests triggers trace with nanosleep syscall, but monitors all syscalls, which results in lot of data in the buffer and makes it harder to debug. Let's lower the trace traffic and monitor just nanosleep syscall. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20211021114132.8196-4-jolsa@kernel.org --- tools/testing/selftests/bpf/progs/test_perf_buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/progs/test_perf_buffer.c b/tools/testing/selftests/bpf/progs/test_perf_buffer.c index d37ce29fd393..a08874c5bdf2 100644 --- a/tools/testing/selftests/bpf/progs/test_perf_buffer.c +++ b/tools/testing/selftests/bpf/progs/test_perf_buffer.c @@ -12,7 +12,7 @@ struct { __type(value, int); } perf_buf_map SEC(".maps"); -SEC("tp/raw_syscalls/sys_enter") +SEC("tp/syscalls/sys_enter_nanosleep") int handle_sys_enter(void *ctx) { int cpu = bpf_get_smp_processor_id();