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Subject[RFC PATCH v2 07/13] perf pmu: Add pmu_id()
Date
Add a function to read the PMU id sysfs entry. We only do it for uncore
PMUs where this would be relevant.

Signed-off-by: John Garry <john.garry@huawei.com>
---
tools/perf/util/pmu.c | 36 ++++++++++++++++++++++++++++++++++++
tools/perf/util/pmu.h | 1 +
2 files changed, 37 insertions(+)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index ef6a63f3d386..6a67c6a28d08 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -594,6 +594,7 @@ static struct perf_cpu_map *__pmu_cpumask(const char *path)
* Uncore PMUs have a "cpumask" file under sysfs. CPU PMUs (e.g. on arm/arm64)
* may have a "cpus" file.
*/
+#define CPUS_TEMPLATE_ID "%s/bus/event_source/devices/%s/identifier"
#define CPUS_TEMPLATE_UNCORE "%s/bus/event_source/devices/%s/cpumask"
#define CPUS_TEMPLATE_CPU "%s/bus/event_source/devices/%s/cpus"

@@ -632,6 +633,39 @@ static bool pmu_is_uncore(const char *name)
return file_available(path);
}

+static char *pmu_id(const char *name)
+{
+ char path[PATH_MAX], *id;
+ const char *sysfs;
+ FILE *file;
+ int n;
+
+ sysfs = sysfs__mountpoint();
+ snprintf(path, PATH_MAX, CPUS_TEMPLATE_ID, sysfs, name);
+
+ id = malloc(PATH_MAX);
+ if (!id)
+ return NULL;
+
+ file = fopen(path, "r");
+ if (!file) {
+ free(id);
+ return NULL;
+ }
+
+ n = fscanf(file, "%s", id);
+
+ fclose(file);
+
+ if (!n) {
+ free(id);
+ return NULL;
+ }
+
+ return id;
+}
+
+
/*
* PMU CORE devices have different name other than cpu in sysfs on some
* platforms.
@@ -844,6 +878,8 @@ static struct perf_pmu *pmu_lookup(const char *name)
pmu->name = strdup(name);
pmu->type = type;
pmu->is_uncore = pmu_is_uncore(name);
+ if (pmu->is_uncore)
+ pmu->id = pmu_id(name);
pmu->max_precise = pmu_max_precise(name);
pmu_add_cpu_aliases(&aliases, pmu);

diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index 5fb3f16828df..62ebca9481fe 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -24,6 +24,7 @@ struct perf_event_attr;

struct perf_pmu {
char *name;
+ char *id;
__u32 type;
bool selectable;
bool is_uncore;
--
2.16.4
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