perf test pmu: Add an eagerly loaded event test

Allow events/aliases to be eagerly loaded for a PMU. Factor out the
pmu_aliases_parse to allow this.

Parse a test event and check it configures the attribute as expected.

There is overlap with the parse-events tests, but this test is done with
a PMU created in a temp directory and doesn't rely on PMUs in sysfs.

Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: https://lore.kernel.org/r/20240502213507.2339733-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 48 insertions, 21 deletions

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index fbbc535ed93f..7849be4bfea1 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -597,33 +597,18 @@ static inline bool pmu_alias_info_file(const char *name)
  * Reading the pmu event aliases definition, which should be located at:
  * /sys/bus/event_source/devices/<dev>/events as sysfs group attributes.
  */
-static int pmu_aliases_parse(struct perf_pmu *pmu)
+static int __pmu_aliases_parse(struct perf_pmu *pmu, int events_dir_fd)
 {
-	char path[PATH_MAX];
 	struct dirent *evt_ent;
 	DIR *event_dir;
-	size_t len;
-	int fd, dir_fd;
 
-	len = perf_pmu__event_source_devices_scnprintf(path, sizeof(path));
-	if (!len)
-		return 0;
-	scnprintf(path + len, sizeof(path) - len, "%s/events", pmu->name);
-
-	dir_fd = open(path, O_DIRECTORY);
-	if (dir_fd == -1) {
-		pmu->sysfs_aliases_loaded = true;
-		return 0;
-	}
-
-	event_dir = fdopendir(dir_fd);
-	if (!event_dir){
-		close (dir_fd);
+	event_dir = fdopendir(events_dir_fd);
+	if (!event_dir)
 		return -EINVAL;
-	}
 
 	while ((evt_ent = readdir(event_dir))) {
 		char *name = evt_ent->d_name;
+		int fd;
 		FILE *file;
 
 		if (!strcmp(name, ".") || !strcmp(name, ".."))
@@ -635,7 +620,7 @@ static int pmu_aliases_parse(struct perf_pmu *pmu)
 		if (pmu_alias_info_file(name))
 			continue;
 
-		fd = openat(dir_fd, name, O_RDONLY);
+		fd = openat(events_dir_fd, name, O_RDONLY);
 		if (fd == -1) {
 			pr_debug("Cannot open %s\n", name);
 			continue;
@@ -653,11 +638,50 @@ static int pmu_aliases_parse(struct perf_pmu *pmu)
 	}
 
 	closedir(event_dir);
-	close (dir_fd);
 	pmu->sysfs_aliases_loaded = true;
 	return 0;
 }
 
+static int pmu_aliases_parse(struct perf_pmu *pmu)
+{
+	char path[PATH_MAX];
+	size_t len;
+	int events_dir_fd, ret;
+
+	if (pmu->sysfs_aliases_loaded)
+		return 0;
+
+	len = perf_pmu__event_source_devices_scnprintf(path, sizeof(path));
+	if (!len)
+		return 0;
+	scnprintf(path + len, sizeof(path) - len, "%s/events", pmu->name);
+
+	events_dir_fd = open(path, O_DIRECTORY);
+	if (events_dir_fd == -1) {
+		pmu->sysfs_aliases_loaded = true;
+		return 0;
+	}
+	ret = __pmu_aliases_parse(pmu, events_dir_fd);
+	close(events_dir_fd);
+	return ret;
+}
+
+static int pmu_aliases_parse_eager(struct perf_pmu *pmu, int sysfs_fd)
+{
+	char path[FILENAME_MAX + 7];
+	int ret, events_dir_fd;
+
+	scnprintf(path, sizeof(path), "%s/events", pmu->name);
+	events_dir_fd = openat(sysfs_fd, path, O_DIRECTORY, 0);
+	if (events_dir_fd == -1) {
+		pmu->sysfs_aliases_loaded = true;
+		return 0;
+	}
+	ret = __pmu_aliases_parse(pmu, events_dir_fd);
+	close(events_dir_fd);
+	return ret;
+}
+
 static int pmu_alias_terms(struct perf_pmu_alias *alias, int err_loc, struct list_head *terms)
 {
 	struct parse_events_term *term, *cloned;
@@ -1042,6 +1066,9 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char
 
 	perf_pmu__arch_init(pmu);
 
+	if (eager_load)
+		pmu_aliases_parse_eager(pmu, dirfd);
+
 	return pmu;
 err:
 	zfree(&pmu->name);