Commit d4b54054 authored by Mykola Lysenko's avatar Mykola Lysenko Committed by Andrii Nakryiko
Browse files

Improve perf related BPF tests (sample_freq issue) 



Linux kernel may automatically reduce kernel.perf_event_max_sample_rate
value when running tests in parallel on slow systems. Linux kernel checks
against this limit when opening perf event with freq=1 parameter set.
The lower bound is 1000. This patch reduces sample_freq value to 1000
in all BPF tests that use sample_freq to ensure they always can open
perf event.

Signed-off-by: default avatarMykola Lysenko <mykolal@fb.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220308200449.1757478-2-mykolal@fb.com
parent 7fd9fd46

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

+1 −1
Original line number Diff line number Diff line
@@ -199,7 +199,7 @@ static void pe_subtest(struct test_bpf_cookie *skel) 
	attr.type = PERF_TYPE_SOFTWARE;

	attr.config = PERF_COUNT_SW_CPU_CLOCK;

	attr.freq = 1;

	attr.sample_freq = 4000;

	attr.sample_freq = 1000;

	pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);

	if (!ASSERT_GE(pfd, 0, "perf_fd"))

		goto cleanup;

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

+1 −1
Original line number Diff line number Diff line
@@ -30,7 +30,7 @@ static int open_pe(void) 
	attr.type = PERF_TYPE_HARDWARE;

	attr.config = PERF_COUNT_HW_CPU_CYCLES;

	attr.freq = 1;

	attr.sample_freq = 4000;

	attr.sample_freq = 1000;

	pfd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, PERF_FLAG_FD_CLOEXEC);



	return pfd >= 0 ? pfd : -errno;

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

+2 −2
Original line number Diff line number Diff line
@@ -110,7 +110,7 @@ static void test_perf_branches_hw(void) 
	attr.type = PERF_TYPE_HARDWARE;

	attr.config = PERF_COUNT_HW_CPU_CYCLES;

	attr.freq = 1;

	attr.sample_freq = 4000;

	attr.sample_freq = 1000;

	attr.sample_type = PERF_SAMPLE_BRANCH_STACK;

	attr.branch_sample_type = PERF_SAMPLE_BRANCH_USER | PERF_SAMPLE_BRANCH_ANY;

	pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
@@ -151,7 +151,7 @@ static void test_perf_branches_no_hw(void) 
	attr.type = PERF_TYPE_SOFTWARE;

	attr.config = PERF_COUNT_SW_CPU_CLOCK;

	attr.freq = 1;

	attr.sample_freq = 4000;

	attr.sample_freq = 1000;

	pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);

	if (CHECK(pfd < 0, "perf_event_open", "err %d\n", pfd))

		return;

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

+1 −1
Original line number Diff line number Diff line
@@ -39,7 +39,7 @@ void serial_test_perf_link(void) 
	attr.type = PERF_TYPE_SOFTWARE;

	attr.config = PERF_COUNT_SW_CPU_CLOCK;

	attr.freq = 1;

	attr.sample_freq = 4000;

	attr.sample_freq = 1000;

	pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);

	if (!ASSERT_GE(pfd, 0, "perf_fd"))

		goto cleanup;