perf tools: Add stat event read function

Introducing the perf_event__process_stat_event function to process a
'struct perf_stat' data from a stat event.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Kan Liang <kan.liang@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1445784728-21732-17-git-send-email-jolsa@kernel.org
[ Renamed 'stat' parameter to 'st' to fix 'already defined' build error with older distros (e.g. RHEL6.7) ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/stat.c

@@ -341,3 +341,26 @@ int perf_stat_process_counter(struct perf_stat_config *config,
 
 	return 0;
 }
+
+int perf_event__process_stat_event(struct perf_tool *tool __maybe_unused,
+				   union perf_event *event,
+				   struct perf_session *session)
+{
+	struct perf_counts_values count;
+	struct stat_event *st = &event->stat;
+	struct perf_evsel *counter;
+
+	count.val = st->val;
+	count.ena = st->ena;
+	count.run = st->run;
+
+	counter = perf_evlist__id2evsel(session->evlist, st->id);
+	if (!counter) {
+		pr_err("Failed to resolve counter for stat event.\n");
+		return -EINVAL;
+	}
+
+	*perf_counts(counter->counts, st->cpu, st->thread) = count;
+	counter->supported = true;
+	return 0;
+}

tools/perf/util/stat.h

@@ -90,4 +90,10 @@ void perf_evlist__reset_stats(struct perf_evlist *evlist);
 
 int perf_stat_process_counter(struct perf_stat_config *config,
 			      struct perf_evsel *counter);
+struct perf_tool;
+union perf_event;
+struct perf_session;
+int perf_event__process_stat_event(struct perf_tool *tool,
+				   union perf_event *event,
+				   struct perf_session *session);
 #endif