perf stat: Add per-core aggregation

This patch adds the --per-core option to perf stat.

This option is used to aggregate system-wide counts
on a per physical core basis. On processors with
hyperthreading, this means counts of all HT threads
running on a physical core are aggregated.

This mode is useful to find imblance between physical
cores running an uniform workload. Cores are identified
by socket: S0-C1, means physical core 1 on socket 0. Note
that cores are identified using their physical core id,
thus their numbering may not be continuous.

Per core aggregation can be combined with interval printing:

 # perf stat -a --per-core -I 1000 -e cycles sleep 1000
 #           time core         cpus             counts events
      1.000090030 S0-C0           1          4,765,747 cycles
      1.000090030 S0-C1           1          5,580,647 cycles
      1.000090030 S0-C2           1            221,181 cycles
      1.000090030 S0-C3           1            266,092 cycles

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1360846649-6411-4-git-send-email-eranian@google.com
[ committer note: Remove parts already applied on 86ee6e1 to keep bisectability ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
index 7bb8e87a5847..beb8cf9f9976 100644
--- a/tools/perf/util/cpumap.c
+++ b/tools/perf/util/cpumap.c
@@ -267,7 +267,53 @@ static int cpu_map__build_map(struct cpu_map *cpus, struct cpu_map **res,
 	return 0;
 }
 
+int cpu_map__get_core(struct cpu_map *map, int idx)
+{
+	FILE *fp;
+	const char *mnt;
+	char path[PATH_MAX];
+	int cpu, ret, s;
+
+	if (idx > map->nr)
+		return -1;
+
+	cpu = map->map[idx];
+
+	mnt = sysfs_find_mountpoint();
+	if (!mnt)
+		return -1;
+
+	snprintf(path, PATH_MAX,
+		"%s/devices/system/cpu/cpu%d/topology/core_id",
+		mnt, cpu);
+
+	fp = fopen(path, "r");
+	if (!fp)
+		return -1;
+	ret = fscanf(fp, "%d", &cpu);
+	fclose(fp);
+	if (ret != 1)
+		return -1;
+
+	s = cpu_map__get_socket(map, idx);
+	if (s == -1)
+		return -1;
+
+	/*
+	 * encode socket in upper 16 bits
+	 * core_id is relative to socket, and
+	 * we need a global id. So we combine
+	 * socket+ core id
+	 */
+	return (s << 16) | (cpu & 0xffff);
+}
+
 int cpu_map__build_socket_map(struct cpu_map *cpus, struct cpu_map **sockp)
 {
 	return cpu_map__build_map(cpus, sockp, cpu_map__get_socket);
 }
+
+int cpu_map__build_core_map(struct cpu_map *cpus, struct cpu_map **corep)
+{
+	return cpu_map__build_map(cpus, corep, cpu_map__get_core);
+}