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>

2 files changed, 58 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);
+}
diff --git a/tools/perf/util/cpumap.h b/tools/perf/util/cpumap.h
index 161b00756a12..9bed02e5fb3d 100644
--- a/tools/perf/util/cpumap.h
+++ b/tools/perf/util/cpumap.h
@@ -15,7 +15,9 @@ void cpu_map__delete(struct cpu_map *map);
 struct cpu_map *cpu_map__read(FILE *file);
 size_t cpu_map__fprintf(struct cpu_map *map, FILE *fp);
 int cpu_map__get_socket(struct cpu_map *map, int idx);
+int cpu_map__get_core(struct cpu_map *map, int idx);
 int cpu_map__build_socket_map(struct cpu_map *cpus, struct cpu_map **sockp);
+int cpu_map__build_core_map(struct cpu_map *cpus, struct cpu_map **corep);
 
 static inline int cpu_map__socket(struct cpu_map *sock, int s)
 {
@@ -24,6 +26,16 @@ static inline int cpu_map__socket(struct cpu_map *sock, int s)
         return sock->map[s];
 }
 
+static inline int cpu_map__id_to_socket(int id)
+{
+        return id >> 16;
+}
+
+static inline int cpu_map__id_to_cpu(int id)
+{
+        return id & 0xffff;
+}
+
 static inline int cpu_map__nr(const struct cpu_map *map)
 {
         return map ? map->nr : 1;