Re: [RFC PATCH v2 07/13] perf pmu: Add pmu_id()
From: John Garry
Date: Wed Apr 22 2020 - 07:55:33 EST
Wi
On 22/04/2020 12:41, Jiri Olsa wrote:
On Fri, Apr 17, 2020 at 06:41:18PM +0800, John Garry wrote:
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@xxxxxxxxxx>
---
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;
+}
I still need to go through this patchset in more detail,
ok, great.
But, could you check patch #1 also, as this *may* be fixing something
broken in mainline? Not sure. Without it, we get a spew of warnings for
metrics.
but just quick note, that we have sysfs__read_str that you
could use in here
ok, there may be more functions in current pmu.c then which can use
this. I can check.
Cheers,
John