perf tools: Add event_update event name type

Adding name type 'event update' event, that stores/transfer events name.
Event's name is stored within perf.data's EVENT_DESC feature, but we
don't have it if we get the report data from pipe.

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/1445784728-21732-24-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/event_update.c

@@ -34,10 +34,30 @@ static int process_event_scale(struct perf_tool *tool __maybe_unused,
 	return 0;
 }
 
+struct event_name {
+	struct perf_tool tool;
+	const char *name;
+};
+
+static int process_event_name(struct perf_tool *tool,
+			      union perf_event *event,
+			      struct perf_sample *sample __maybe_unused,
+			      struct machine *machine __maybe_unused)
+{
+	struct event_name *tmp = container_of(tool, struct event_name, tool);
+	struct event_update_event *ev = (struct event_update_event*) event;
+
+	TEST_ASSERT_VAL("wrong id", ev->id == 123);
+	TEST_ASSERT_VAL("wrong id", ev->type == PERF_EVENT_UPDATE__NAME);
+	TEST_ASSERT_VAL("wrong name", !strcmp(ev->data, tmp->name));
+	return 0;
+}
+
 int test__event_update(int subtest __maybe_unused)
 {
 	struct perf_evlist *evlist;
 	struct perf_evsel *evsel;
+	struct event_name tmp;
 
 	evlist = perf_evlist__new_default();
 	TEST_ASSERT_VAL("failed to get evlist", evlist);
@@ -59,5 +79,10 @@ int test__event_update(int subtest __maybe_unused)
 	TEST_ASSERT_VAL("failed to synthesize attr update scale",
 			!perf_event__synthesize_event_update_scale(NULL, evsel, process_event_scale));
 
+	tmp.name = perf_evsel__name(evsel);
+
+	TEST_ASSERT_VAL("failed to synthesize attr update name",
+			!perf_event__synthesize_event_update_name(&tmp.tool, evsel, process_event_name));
+
 	return 0;
 }

tools/perf/util/event.h

@@ -311,6 +311,7 @@ struct attr_event {
 enum {
 	PERF_EVENT_UPDATE__UNIT  = 0,
 	PERF_EVENT_UPDATE__SCALE = 1,
+	PERF_EVENT_UPDATE__NAME  = 2,
 };
 
 struct event_update_event_scale {

tools/perf/util/header.c

@@ -2743,6 +2743,24 @@ perf_event__synthesize_event_update_scale(struct perf_tool *tool,
 	return err;
 }
 
+int
+perf_event__synthesize_event_update_name(struct perf_tool *tool,
+					 struct perf_evsel *evsel,
+					 perf_event__handler_t process)
+{
+	struct event_update_event *ev;
+	size_t len = strlen(evsel->name);
+	int err;
+
+	ev = event_update_event__new(len + 1, PERF_EVENT_UPDATE__NAME, evsel->id[0]);
+	if (ev == NULL)
+		return -ENOMEM;
+
+	strncpy(ev->data, evsel->name, len);
+	err = process(tool, (union perf_event*) ev, NULL, NULL);
+	free(ev);
+	return err;
+}
 
 int perf_event__synthesize_attrs(struct perf_tool *tool,
 				   struct perf_session *session,
@@ -2825,6 +2843,9 @@ int perf_event__process_event_update(struct perf_tool *tool __maybe_unused,
 	case PERF_EVENT_UPDATE__UNIT:
 		evsel->unit = strdup(ev->data);
 		break;
+	case PERF_EVENT_UPDATE__NAME:
+		evsel->name = strdup(ev->data);
+		break;
 	case PERF_EVENT_UPDATE__SCALE:
 		ev_scale = (struct event_update_event_scale *) ev->data;
 		evsel->scale = ev_scale->scale;

tools/perf/util/header.h

@@ -111,6 +111,9 @@ int perf_event__synthesize_event_update_unit(struct perf_tool *tool,
 int perf_event__synthesize_event_update_scale(struct perf_tool *tool,
 					      struct perf_evsel *evsel,
 					      perf_event__handler_t process);
+int perf_event__synthesize_event_update_name(struct perf_tool *tool,
+					     struct perf_evsel *evsel,
+					     perf_event__handler_t process);
 int perf_event__process_attr(struct perf_tool *tool, union perf_event *event,
 			     struct perf_evlist **pevlist);
 int perf_event__process_event_update(struct perf_tool *tool __maybe_unused,