diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 0b38c51bd6eb..ef8ab918eaeb 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -367,8 +367,8 @@ static int perf_pmu__parse_unit(struct perf_pmu *pmu, struct perf_pmu_alias *ali
 	return -1;
 }
 
-static int
-perf_pmu__parse_per_pkg(struct perf_pmu *pmu, struct perf_pmu_alias *alias)
+static bool perf_pmu__parse_event_source_bool(const char *pmu_name, const char *event_name,
+					      const char *suffix)
 {
 	char path[PATH_MAX];
 	size_t len;
@@ -376,37 +376,36 @@ perf_pmu__parse_per_pkg(struct perf_pmu *pmu, struct perf_pmu_alias *alias)
 
 	len = perf_pmu__event_source_devices_scnprintf(path, sizeof(path));
 	if (!len)
-		return 0;
-	scnprintf(path + len, sizeof(path) - len, "%s/events/%s.per-pkg", pmu->name, alias->name);
+		return false;
+
+	scnprintf(path + len, sizeof(path) - len, "%s/events/%s.%s", pmu_name, event_name, suffix);
 
 	fd = open(path, O_RDONLY);
 	if (fd == -1)
-		return -1;
+		return false;
+
+#ifndef NDEBUG
+	{
+		char buf[8];
+
+		len = read(fd, buf, sizeof(buf));
+		assert(len == 1 || len == 2);
+		assert(buf[0] == '1');
+	}
+#endif
 
 	close(fd);
-
-	alias->per_pkg = true;
-	return 0;
+	return true;
 }
 
-static int perf_pmu__parse_snapshot(struct perf_pmu *pmu, struct perf_pmu_alias *alias)
+static void perf_pmu__parse_per_pkg(struct perf_pmu *pmu, struct perf_pmu_alias *alias)
 {
-	char path[PATH_MAX];
-	size_t len;
-	int fd;
+	alias->per_pkg = perf_pmu__parse_event_source_bool(pmu->name, alias->name, "per-pkg");
+}
 
-	len = perf_pmu__event_source_devices_scnprintf(path, sizeof(path));
-	if (!len)
-		return 0;
-	scnprintf(path + len, sizeof(path) - len, "%s/events/%s.snapshot", pmu->name, alias->name);
-
-	fd = open(path, O_RDONLY);
-	if (fd == -1)
-		return -1;
-
-	alias->snapshot = true;
-	close(fd);
-	return 0;
+static void perf_pmu__parse_snapshot(struct perf_pmu *pmu, struct perf_pmu_alias *alias)
+{
+	alias->snapshot = perf_pmu__parse_event_source_bool(pmu->name, alias->name, "snapshot");
 }
 
 /* Delete an alias entry. */