[igt-dev] [PATCH i-g-t v2] tests/i915/perf_pmu: Add a basic perf_pmu test

[Riana Tauro <riana.tauro@intel.com>]

add a test that verifies the i915 pmu directory and
reads all the events

v2 : use igt_assert_eq instead of igt_assert
     check errno after loop (Umesh)

Signed-off-by: Riana Tauro <riana.tauro@intel.com>
---
 lib/igt_perf.c        | 11 +++++++++++
 lib/igt_perf.h        |  1 +
 tests/i915/perf_pmu.c | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/lib/igt_perf.c b/lib/igt_perf.c
index 11c91c5f..ffe078ad 100644
--- a/lib/igt_perf.c
+++ b/lib/igt_perf.c
@@ -1,5 +1,6 @@
 #include <errno.h>
 #include <fcntl.h>
+#include <limits.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
@@ -98,6 +99,16 @@ uint64_t igt_perf_type_id(const char *device)
 	return strtoull(buf, NULL, 0);
 }
 
+int igt_perf_events_dir(int i915)
+{
+	char buf[80];
+	char path[PATH_MAX];
+
+	i915_perf_device(i915, buf, sizeof(buf));
+	snprintf(path, sizeof(path), "/sys/bus/event_source/devices/%s/events", buf);
+	return open(path, O_RDONLY);
+}
+
 static int
 _perf_open(uint64_t type, uint64_t config, int group, uint64_t format)
 {
diff --git a/lib/igt_perf.h b/lib/igt_perf.h
index 672bfea6..4d86e31a 100644
--- a/lib/igt_perf.h
+++ b/lib/igt_perf.h
@@ -54,6 +54,7 @@ perf_event_open(struct perf_event_attr *attr,
 }
 
 uint64_t igt_perf_type_id(const char *device);
+int igt_perf_events_dir(int i915);
 int igt_perf_open(uint64_t type, uint64_t config);
 int igt_perf_open_group(uint64_t type, uint64_t config, int group);
 
diff --git a/tests/i915/perf_pmu.c b/tests/i915/perf_pmu.c
index f363db2b..c1779fc9 100644
--- a/tests/i915/perf_pmu.c
+++ b/tests/i915/perf_pmu.c
@@ -2132,6 +2132,34 @@ static void test_unload(unsigned int num_engines)
 	igt_assert_eq(__igt_i915_driver_unload(NULL), 0);
 }
 
+static void pmu_read(int i915)
+{
+	char val[128];
+	int pmu_fd;
+	struct dirent *de;
+	DIR *dir;
+
+	pmu_fd = igt_perf_events_dir(i915);
+	igt_require(pmu_fd >= 0);
+
+	dir = fdopendir(dup(pmu_fd));
+	igt_assert(dir);
+	rewinddir(dir);
+
+	errno = 0;
+	while ((de = readdir(dir))) {
+		if (de->d_type != DT_REG)
+			continue;
+
+		igt_assert_eq(igt_sysfs_scanf(pmu_fd, de->d_name, "%127s", val), 1);
+		igt_debug("'%s': %s\n", de->d_name, val);
+	}
+
+	igt_assert_eq(errno, 0);
+	closedir(dir);
+	close(pmu_fd);
+}
+
 #define test_each_engine(T, i915, ctx, e) \
 	igt_subtest_with_dynamic(T) for_each_ctx_engine(i915, ctx, e) \
 		igt_dynamic_f("%s", e->name)
@@ -2167,6 +2195,10 @@ igt_main
 		igt_require(num_engines);
 	}
 
+	igt_describe("Verify i915 pmu dir exists and read all events");
+	igt_subtest("pmu-read")
+		pmu_read(fd);
+
 	/**
 	 * Test invalid access via perf API is rejected.
 	 */
-- 
2.39.0