perf metricgroup: Always place duration_time last

If a metric contains the duration_time event then the event is placed
outside of the metric's group of events. Rather than split the group,
make it so the duration_time is immediately after the group.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200520182011.32236-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/metricgroup.c

@@ -413,8 +413,8 @@ static void metricgroup__add_metric_weak_group(struct strbuf *events,
 					       struct expr_parse_ctx *ctx)
 {
 	struct hashmap_entry *cur;
-	size_t bkt, i = 0;
+	size_t bkt;
-	bool no_group = false;
+	bool no_group = true, has_duration = false;
 
 	hashmap__for_each_entry((&ctx->ids), cur, bkt) {
 		pr_debug("found event %s\n", (const char *)cur->key);
@@ -424,20 +424,20 @@ static void metricgroup__add_metric_weak_group(struct strbuf *events,
 		 * group.
 		 */
 		if (!strcmp(cur->key, "duration_time")) {
-			if (i > 0)
+			has_duration = true;
-				strbuf_addf(events, "}:W,");
-			strbuf_addf(events, "duration_time");
-			no_group = true;
 			continue;
 		}
 		strbuf_addf(events, "%s%s",
-			i == 0 || no_group ? "{" : ",",
+			no_group ? "{" : ",",
 			(const char *)cur->key);
 		no_group = false;
-		i++;
 	}
-	if (!no_group)
+	if (!no_group) {
 		strbuf_addf(events, "}:W");
+		if (has_duration)
+			strbuf_addf(events, ",duration_time");
+	} else if (has_duration)
+		strbuf_addf(events, "duration_time");
 }
 
 static void metricgroup__add_metric_non_group(struct strbuf *events,