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: Mykola Lysenko <mykolal@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220308200449.1757478-2-mykolal@fb.com

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

@@ -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

@@ -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

@@ -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

@@ -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;