[PATCH v2 4/4] perf test: Add user space counter reading tests

From: Ian Rogers
Date: Thu Jun 09 2022 - 01:24:34 EST


These tests are based on test_stat_user_read in
tools/lib/perf/tests/test-evsel.c. The tests are modified to skip if
perf_event_open fails or rdpmc isn't supported.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
tools/perf/tests/mmap-basic.c | 127 +++++++++++++++++++++++++++++++++-
1 file changed, 126 insertions(+), 1 deletion(-)

diff --git a/tools/perf/tests/mmap-basic.c b/tools/perf/tests/mmap-basic.c
index 30bbe144648a..dfb6173b2a82 100644
--- a/tools/perf/tests/mmap-basic.c
+++ b/tools/perf/tests/mmap-basic.c
@@ -170,14 +170,139 @@ static int test__basic_mmap(struct test_suite *test __maybe_unused, int subtest
return err;
}

+static int test_stat_user_read(int event)
+{
+ struct perf_counts_values counts = { .val = 0 };
+ struct perf_thread_map *threads;
+ struct perf_evsel *evsel;
+ struct perf_event_mmap_page *pc;
+ struct perf_event_attr attr = {
+ .type = PERF_TYPE_HARDWARE,
+ .config = event,
+#ifdef __aarch64__
+ .config1 = 0x2, /* Request user access */
+#endif
+ };
+ int err, i, ret = TEST_FAIL;
+ bool opened = false, mapped = false;
+
+ threads = perf_thread_map__new_dummy();
+ TEST_ASSERT_VAL("failed to create threads", threads);
+
+ perf_thread_map__set_pid(threads, 0, 0);
+
+ evsel = perf_evsel__new(&attr);
+ TEST_ASSERT_VAL("failed to create evsel", evsel);
+
+ err = perf_evsel__open(evsel, NULL, threads);
+ if (err) {
+ pr_err("failed to open evsel: %s\n", strerror(-err));
+ ret = TEST_SKIP;
+ goto out;
+ }
+ opened = true;
+
+ err = perf_evsel__mmap(evsel, 0);
+ if (err) {
+ pr_err("failed to mmap evsel: %s\n", strerror(-err));
+ goto out;
+ }
+ mapped = true;
+
+ pc = perf_evsel__mmap_base(evsel, 0, 0);
+ if (!pc) {
+ pr_err("failed to get mmapped address\n");
+ goto out;
+ }
+
+ if (!pc->cap_user_rdpmc || !pc->index) {
+ pr_err("userspace counter access not %s\n",
+ !pc->cap_user_rdpmc ? "supported" : "enabled");
+ ret = TEST_SKIP;
+ goto out;
+ }
+ if (pc->pmc_width < 32) {
+ pr_err("userspace counter width not set (%d)\n", pc->pmc_width);
+ goto out;
+ }
+
+ perf_evsel__read(evsel, 0, 0, &counts);
+ if (counts.val == 0) {
+ pr_err("failed to read value for evsel\n");
+ goto out;
+ }
+
+ for (i = 0; i < 5; i++) {
+ volatile int count = 0x10000 << i;
+ __u64 start, end, last = 0;
+
+ pr_debug("\tloop = %u, ", count);
+
+ perf_evsel__read(evsel, 0, 0, &counts);
+ start = counts.val;
+
+ while (count--) ;
+
+ perf_evsel__read(evsel, 0, 0, &counts);
+ end = counts.val;
+
+ if ((end - start) < last) {
+ pr_err("invalid counter data: end=%llu start=%llu last= %llu\n",
+ end, start, last);
+ goto out;
+ }
+ last = end - start;
+ pr_debug("count = %llu\n", end - start);
+ }
+ ret = TEST_OK;
+
+out:
+ if (mapped)
+ perf_evsel__munmap(evsel);
+ if (opened)
+ perf_evsel__close(evsel);
+ perf_evsel__delete(evsel);
+
+ perf_thread_map__put(threads);
+ return ret;
+}
+
+static int test__mmap_user_read_instr(struct test_suite *test __maybe_unused,
+ int subtest __maybe_unused)
+{
+ return test_stat_user_read(PERF_COUNT_HW_INSTRUCTIONS);
+}
+
+static int test__mmap_user_read_cycles(struct test_suite *test __maybe_unused,
+ int subtest __maybe_unused)
+{
+ return test_stat_user_read(PERF_COUNT_HW_CPU_CYCLES);
+}
+
static struct test_case tests__basic_mmap[] = {
TEST_CASE_REASON("Read samples using the mmap interface",
basic_mmap,
"permissions"),
+ TEST_CASE_REASON("User space counter reading of instructions",
+ mmap_user_read_instr,
+#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__)
+ "permissions"
+#else
+ "unsupported"
+#endif
+ ),
+ TEST_CASE_REASON("User space counter reading of cycles",
+ mmap_user_read_cycles,
+#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__)
+ "permissions"
+#else
+ "unsupported"
+#endif
+ ),
{ .name = NULL, }
};

struct test_suite suite__basic_mmap = {
- .desc = "Read samples using the mmap interface",
+ .desc = "mmap interface tests",
.test_cases = tests__basic_mmap,
};
--
2.36.1.255.ge46751e96f-goog