perf stat: Use perf_evsel__read_cb in read_counter

Replacing __perf_evsel__read_on_cpu function with perf_evsel__read_cb
function. The read_cb callback will be used later for global aggregation
counter values as well.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1416562275-12404-5-git-send-email-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-stat.c

@@ -388,6 +388,26 @@ static void update_shadow_stats(struct perf_evsel *counter, u64 *count)
 		update_stats(&runtime_itlb_cache_stats[0], count[0]);
 }
 
+static int read_cb(struct perf_evsel *evsel, int cpu, int thread __maybe_unused,
+		   struct perf_counts_values *count)
+{
+	switch (aggr_mode) {
+	case AGGR_CORE:
+	case AGGR_SOCKET:
+	case AGGR_NONE:
+		perf_evsel__compute_deltas(evsel, cpu, count);
+		perf_counts_values__scale(count, scale, NULL);
+		evsel->counts->cpu[cpu] = *count;
+		update_shadow_stats(evsel, count->values);
+		break;
+	case AGGR_GLOBAL:
+	default:
+		break;
+	}
+
+	return 0;
+}
+
 /*
  * Read out the results of a single counter:
  * aggregate counts across CPUs in system-wide mode
@@ -424,16 +444,11 @@ static int read_counter_aggr(struct perf_evsel *counter)
  */
 static int read_counter(struct perf_evsel *counter)
 {
-	u64 *count;
 	int cpu;
 
 	for (cpu = 0; cpu < perf_evsel__nr_cpus(counter); cpu++) {
-		if (__perf_evsel__read_on_cpu(counter, cpu, 0, scale) < 0)
+		if (perf_evsel__read_cb(counter, cpu, 0, read_cb))
 			return -1;
-
-		count = counter->counts->cpu[cpu].values;
-
-		update_shadow_stats(counter, count);
 	}
 
 	return 0;