perf pmu: Display pmu name when printing unmerged events in stat

To simplify creation of events accross multiple instances of the same
type of PMU stat supports two methods for creating multiple events from
a single event specification:

1. A prefix or glob can be used in the PMU name.
2. Aliases, which are listed immediately after the Kernel PMU events
   by perf list, are used.

When the --no-merge option is passed and these events are displayed
individually the PMU name is lost and it's not possible to see which
count corresponds to which pmu:

    $ perf stat -a -e l3cache/read-miss/ --no-merge ls > /dev/null

     Performance counter stats for 'system wide':

                    67      l3cache/read-miss/
                    67      l3cache/read-miss/
                    63      l3cache/read-miss/
                    60      l3cache/read-miss/

           0.001675706 seconds time elapsed

    $ perf stat -a -e l3cache_read_miss --no-merge ls > /dev/null

     Performance counter stats for 'system wide':

                    12      l3cache_read_miss
                    17      l3cache_read_miss
                    10      l3cache_read_miss
                     8      l3cache_read_miss

           0.001661305 seconds time elapsed

This change adds the original pmu name to the event. For dynamic pmu
events the pmu name is restored in the event name:

    $ perf stat -a -e l3cache/read-miss/ --no-merge ls > /dev/null

     Performance counter stats for 'system wide':

                    63      l3cache_0_3/read-miss/
                    74      l3cache_0_1/read-miss/
                    64      l3cache_0_2/read-miss/
                    74      l3cache_0_0/read-miss/

           0.001675706 seconds time elapsed

For alias events the name is added after the event name:

    $ perf stat -a -e l3cache_read_miss --no-merge ls > /dev/null

     Performance counter stats for 'system wide':

                    10      l3cache_read_miss [l3cache_0_3]
                    12      l3cache_read_miss [l3cache_0_1]
                    10      l3cache_read_miss [l3cache_0_2]
                    17      l3cache_read_miss [l3cache_0_0]

           0.001661305 seconds time elapsed

Signed-off-by: Agustin Vega-Frias <agustinv@codeaurora.org>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Timur Tabi <timur@codeaurora.org>
Cc: linux-arm-kernel@lists.infradead.org
Change-Id: I8056b9eda74bda33e95065056167ad96e97cb1fb
Link: http://lkml.kernel.org/r/1520345084-42646-3-git-send-email-agustinv@codeaurora.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-stat.c

@@ -1251,6 +1251,31 @@ static void aggr_update_shadow(void)
 	}
 }
 
+static void uniquify_event_name(struct perf_evsel *counter)
+{
+	char *new_name;
+	char *config;
+
+	if (!counter->pmu_name || !strncmp(counter->name, counter->pmu_name,
+					   strlen(counter->pmu_name)))
+		return;
+
+	config = strchr(counter->name, '/');
+	if (config) {
+		if (asprintf(&new_name,
+			     "%s%s", counter->pmu_name, config) > 0) {
+			free(counter->name);
+			counter->name = new_name;
+		}
+	} else {
+		if (asprintf(&new_name,
+			     "%s [%s]", counter->name, counter->pmu_name) > 0) {
+			free(counter->name);
+			counter->name = new_name;
+		}
+	}
+}
+
 static void collect_all_aliases(struct perf_evsel *counter,
 			    void (*cb)(struct perf_evsel *counter, void *data,
 				       bool first),
@@ -1279,7 +1304,9 @@ static bool collect_data(struct perf_evsel *counter,
 	if (counter->merged_stat)
 		return false;
 	cb(counter, data, true);
-	if (!no_merge && counter->auto_merge_stats)
+	if (no_merge)
+		uniquify_event_name(counter);
+	else if (counter->auto_merge_stats)
 		collect_all_aliases(counter, cb, data);
 	return true;
 }

tools/perf/util/evsel.c

@@ -244,6 +244,7 @@ void perf_evsel__init(struct perf_evsel *evsel,
 	evsel->metric_name   = NULL;
 	evsel->metric_events = NULL;
 	evsel->collect_stat  = false;
+	evsel->pmu_name      = NULL;
 }
 
 struct perf_evsel *perf_evsel__new_idx(struct perf_event_attr *attr, int idx)

tools/perf/util/evsel.h

@@ -142,6 +142,7 @@ struct perf_evsel {
 	struct perf_evsel	**metric_events;
 	bool			collect_stat;
 	bool			weak_group;
+	const char		*pmu_name;
 };
 
 union u64_swap {

tools/perf/util/parse-events.c

@@ -1247,7 +1247,12 @@ static int __parse_events_add_pmu(struct parse_events_state *parse_state,
 	if (!head_config) {
 		attr.type = pmu->type;
 		evsel = __add_event(list, &parse_state->idx, &attr, NULL, pmu, NULL, auto_merge_stats);
-		return evsel ? 0 : -ENOMEM;
+		if (evsel) {
+			evsel->pmu_name = name;
+			return 0;
+		} else {
+			return -ENOMEM;
+		}
 	}
 
 	if (perf_pmu__check_alias(pmu, head_config, &info))
@@ -1276,6 +1281,7 @@ static int __parse_events_add_pmu(struct parse_events_state *parse_state,
 		evsel->snapshot = info.snapshot;
 		evsel->metric_expr = info.metric_expr;
 		evsel->metric_name = info.metric_name;
+		evsel->pmu_name = name;
 	}
 
 	return evsel ? 0 : -ENOMEM;