perf metric: Add events for the current list

There's no need to iterate the whole list of groups, when adding new
events. The currently created groups are the ones we want to add.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Kajol Jain <kjain@linux.ibm.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200719181320.785305-13-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/metricgroup.c

@@ -827,6 +827,7 @@ static int metricgroup__add_metric(const char *metric, bool metric_no_group,
 {
 	struct pmu_event *pe;
 	struct egroup *eg;
+	LIST_HEAD(list);
 	int i, ret;
 	bool has_match = false;
 
@@ -834,7 +835,7 @@ static int metricgroup__add_metric(const char *metric, bool metric_no_group,
 		has_match = true;
 		eg = NULL;
 
-		ret = add_metric(group_list, pe, metric_no_group, &eg);
+		ret = add_metric(&list, pe, metric_no_group, &eg);
 		if (ret)
 			return ret;
 
@@ -843,7 +844,7 @@ static int metricgroup__add_metric(const char *metric, bool metric_no_group,
 		 * included in the expression.
 		 */
 		ret = resolve_metric(metric_no_group,
-				     group_list, map);
+				     &list, map);
 		if (ret)
 			return ret;
 	}
@@ -852,7 +853,7 @@ static int metricgroup__add_metric(const char *metric, bool metric_no_group,
 	if (!has_match)
 		return -EINVAL;
 
-	list_for_each_entry(eg, group_list, nd) {
+	list_for_each_entry(eg, &list, nd) {
 		if (events->len > 0)
 			strbuf_addf(events, ",");
 
@@ -864,6 +865,8 @@ static int metricgroup__add_metric(const char *metric, bool metric_no_group,
 							   &eg->pctx);
 		}
 	}
+
+	list_splice(&list, group_list);
 	return 0;
 }