Skip to contentSkip to conversation

perf pmu: Add helper function is_pmu_core to detect PMU CORE devices

tip:perf/core tip-bot for Ganapatrao Kulkarni 1 participant 1 message Dec 6, 2017 perf events

lore
Share & tools
lore

tip-bot for Ganapatrao Kulkarni

author merge bot
#0 lore raw
Commit-ID:  14b22ae028de56cca980171db625d1e9925c8fba
Gitweb:     https://git.kernel.org/tip/14b22ae028de56cca980171db625d1e9925c8fba
Author:     Ganapatrao Kulkarni <[email protected]>
AuthorDate: Thu, 24 Aug 2017 16:30:58 +0530
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Tue, 5 Dec 2017 15:43:51 -0300

perf pmu: Add helper function is_pmu_core to detect PMU CORE devices

On some platforms, PMU core devices sysfs name is not cpu. Adding function is_pmu_core to detect PMU core devices using core device specific hints in sysfs.

For arm64 platforms, all core devices have file "cpus" in sysfs.

Signed-off-by Ganapatrao Kulkarni <[email protected]>
Tested-by Shaokun Zhang <[email protected]>
Tested-by Jin Yao <[email protected]>
Acked-by Will Deacon <[email protected]>
Link https://lkml.kernel.org/n/[email protected] open here
Signed-off-by Arnaldo Carvalho de Melo <[email protected]>
---
 tools/perf/util/pmu.c | 39 +++++++++++++++++++++++++++++++++++----
 1 file changed, 35 insertions(+), 4 deletions(-)
tools/perf/util/pmu.c +35 -4
index 4e7dd3a..732ff57 100644
@@ -537,6 +537,34 @@ static bool pmu_is_uncore(const char *name)
 }
 
 /*
+ *  PMU CORE devices have different name other than cpu in sysfs on some
+ *  platforms. looking for possible sysfs files to identify as core device.
+ */
+static int is_pmu_core(const char *name)
+{
+	struct stat st;
+	char path[PATH_MAX];
+	const char *sysfs = sysfs__mountpoint();
+
+	if (!sysfs)
+		return 0;
+
+	/* Look for cpu sysfs (x86 and others) */
+	scnprintf(path, PATH_MAX, "%s/bus/event_source/devices/cpu", sysfs);
+	if ((stat(path, &st) == 0) &&
+			(strncmp(name, "cpu", strlen("cpu")) == 0))
+		return 1;
+
+	/* Look for cpu sysfs (specific to arm) */
+	scnprintf(path, PATH_MAX, "%s/bus/event_source/devices/%s/cpus",
+				sysfs, name);
+	if (stat(path, &st) == 0)
+		return 1;
+
+	return 0;
+}
+
+/*
  * Return the CPU id as a raw string.
  *
  * Each architecture should provide a more precise id string that

@@ -609,7 +637,6 @@ static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
 	 */
 	i = 0;
 	while (1) {
-		const char *pname;
 
 		pe = &map->table[i++];
 		if (!pe->name) {

@@ -618,9 +645,13 @@ static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
 			break;
 		}
 
-		pname = pe->pmu ? pe->pmu : "cpu";
-		if (strncmp(pname, name, strlen(pname)))
-			continue;
+		if (!is_pmu_core(name)) {
+			/* check for uncore devices */
+			if (pe->pmu == NULL)
+				continue;
+			if (strncmp(pe->pmu, name, strlen(pe->pmu)))
+				continue;
+		}
 
 		/* need type casts to override 'const' */
 		__perf_pmu__new_alias(head, NULL, (char *)pe->name,