perf record: Select comm_exec flag if supported

The comm_exec flag on the attribute can later be found in the perf.data
file allowing a tool to know in advance if the captured data has the
flag.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1405332185-4050-5-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/record.c

@@ -69,15 +69,26 @@ static void perf_probe_sample_identifier(struct perf_evsel *evsel)
 	evsel->attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
 }
 
+static void perf_probe_comm_exec(struct perf_evsel *evsel)
+{
+	evsel->attr.comm_exec = 1;
+}
+
 bool perf_can_sample_identifier(void)
 {
 	return perf_probe_api(perf_probe_sample_identifier);
 }
 
+static bool perf_can_comm_exec(void)
+{
+	return perf_probe_api(perf_probe_comm_exec);
+}
+
 void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts)
 {
 	struct perf_evsel *evsel;
 	bool use_sample_identifier = false;
+	bool use_comm_exec;
 
 	/*
 	 * Set the evsel leader links before we configure attributes,
@@ -89,8 +100,13 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts)
 	if (evlist->cpus->map[0] < 0)
 		opts->no_inherit = true;
 
-	evlist__for_each(evlist, evsel)
+	use_comm_exec = perf_can_comm_exec();
+
+	evlist__for_each(evlist, evsel) {
 		perf_evsel__config(evsel, opts);
+		if (!evsel->idx && use_comm_exec)
+			evsel->attr.comm_exec = 1;
+	}
 
 	if (evlist->nr_entries > 1) {
 		struct perf_evsel *first = perf_evlist__first(evlist);