perf pmus: Add notion of default PMU for JSON events

JSON events created in pmu-events.c by jevents.py may not specify a
PMU they are associated with, in which case it is implied that it is
the first core PMU. Care is needed to select this for regular 'cpu',
s390 'cpum_cf' and ARMs many names as at the point the name is first
needed the core PMUs list hasn't been initialized. Add a helper in
perf_pmus to create this value, in the worst case by scanning sysfs.

v2. Add missing close if fdopendir fails.

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: James Clark <james.clark@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/r/20230623043843.4080180-1-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 6142e4710a2f32cf0f6b177f2e24edf4c8be3f9f..963c12f910c5dceb7ae00c767129353aabb54dd0 100644 (file)
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -741,9 +741,11 @@ out:
 }
 
 struct pmu_add_cpu_aliases_map_data {
+       /* List being added to. */
        struct list_head *head;
-       const char *name;
-       const char *cpu_name;
+       /* If a pmu_event lacks a given PMU the default used. */
+       char *default_pmu_name;
+       /* The PMU that we're searching for events for. */
        struct perf_pmu *pmu;
 };
 
@@ -752,37 +754,32 @@ static int pmu_add_cpu_aliases_map_callback(const struct pmu_event *pe,
                                        void *vdata)
 {
        struct pmu_add_cpu_aliases_map_data *data = vdata;
-       const char *pname = pe->pmu ? pe->pmu : data->cpu_name;
+       const char *pname = pe->pmu ?: data->default_pmu_name;
 
-       if (data->pmu->is_uncore && pmu_uncore_alias_match(pname, data->name))
-               goto new_alias;
-
-       if (strcmp(pname, data->name))
-               return 0;
-
-new_alias:
-       /* need type casts to override 'const' */
-       __perf_pmu__new_alias(data->head, -1, (char *)pe->name, (char *)pe->desc,
-                             (char *)pe->event, pe);
+       if (!strcmp(pname, data->pmu->name) ||
+           (data->pmu->is_uncore && pmu_uncore_alias_match(pname, data->pmu->name))) {
+               /* need type casts to override 'const' */
+               __perf_pmu__new_alias(data->head, -1, (char *)pe->name, (char *)pe->desc,
+                                     (char *)pe->event, pe);
+       }
        return 0;
 }
 
 /*
- * From the pmu_events_map, find the table of PMU events that corresponds
- * to the current running CPU. Then, add all PMU events from that table
- * as aliases.
+ * From the pmu_events_table, find the events that correspond to the given
+ * PMU and add them to the list 'head'.
  */
 void pmu_add_cpu_aliases_table(struct list_head *head, struct perf_pmu *pmu,
-                              const struct pmu_events_table *table)
+                       const struct pmu_events_table *table)
 {
        struct pmu_add_cpu_aliases_map_data data = {
                .head = head,
-               .name = pmu->name,
-               .cpu_name = is_sysfs_pmu_core(pmu->name) ? pmu->name : "cpu",
+               .default_pmu_name = perf_pmus__default_pmu_name(),
                .pmu = pmu,
        };
 
        pmu_events_table_for_each_event(table, pmu_add_cpu_aliases_map_callback, &data);
+       free(data.default_pmu_name);
 }
 
 static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)

diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c
index d891d72c824ec3b610fcb0c6209461557461ee01..0866dee3fc62e8d8ce937cc63a0af331b67e4fba 100644 (file)
--- a/tools/perf/util/pmus.c
+++ b/tools/perf/util/pmus.c
@@ -137,8 +137,10 @@ static void pmu_read_sysfs(bool core_only)
                return;
 
        dir = fdopendir(fd);
-       if (!dir)
+       if (!dir) {
+               close(fd);
                return;
+       }
 
        while ((dent = readdir(dir))) {
                if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, ".."))
@@ -524,6 +526,39 @@ bool perf_pmus__supports_extended_type(void)
        return perf_pmus__do_support_extended_type;
 }
 
+char *perf_pmus__default_pmu_name(void)
+{
+       int fd;
+       DIR *dir;
+       struct dirent *dent;
+       char *result = NULL;
+
+       if (!list_empty(&core_pmus))
+               return strdup(list_first_entry(&core_pmus, struct perf_pmu, list)->name);
+
+       fd = perf_pmu__event_source_devices_fd();
+       if (fd < 0)
+               return strdup("cpu");
+
+       dir = fdopendir(fd);
+       if (!dir) {
+               close(fd);
+               return strdup("cpu");
+       }
+
+       while ((dent = readdir(dir))) {
+               if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, ".."))
+                       continue;
+               if (is_pmu_core(dent->d_name)) {
+                       result = strdup(dent->d_name);
+                       break;
+               }
+       }
+
+       closedir(dir);
+       return result ?: strdup("cpu");
+}
+
 struct perf_pmu *evsel__find_pmu(const struct evsel *evsel)
 {
        struct perf_pmu *pmu = evsel->pmu;

diff --git a/tools/perf/util/pmus.h b/tools/perf/util/pmus.h
index d02ffea5d3a4e81ffb3d2d6917819b4f68281df6..a21464432d0f81f6cd244aade7af9d856a618967 100644 (file)
--- a/tools/perf/util/pmus.h
+++ b/tools/perf/util/pmus.h
@@ -20,5 +20,6 @@ void perf_pmus__print_pmu_events(const struct print_callbacks *print_cb, void *p
 bool perf_pmus__have_event(const char *pname, const char *name);
 int perf_pmus__num_core_pmus(void);
 bool perf_pmus__supports_extended_type(void);
+char *perf_pmus__default_pmu_name(void);
 
 #endif /* __PMUS_H */