perf metricgroup: Delay events string creation

Currently event groups are placed into groups_list at the same time as
the events string containing the events is built. Separate these two
operations and build the groups_list first, then the event string from
the groups_list. This adds an ability to reorder the groups_list that
will be used in a later patch.
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/20200520182011.32236-4-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/metricgroup.c

@@ -90,6 +90,7 @@ struct egroup {
 	const char *metric_expr;
 	const char *metric_unit;
 	int runtime;
+	bool has_constraint;
 };
 
 static struct evsel *find_evsel_group(struct evlist *perf_evlist,
@@ -488,8 +489,8 @@ int __weak arch_get_runtimeparam(void)
 	return 1;
 }
 
-static int __metricgroup__add_metric(struct strbuf *events,
-		struct list_head *group_list, struct pmu_event *pe, int runtime)
+static int __metricgroup__add_metric(struct list_head *group_list,
+				     struct pmu_event *pe, int runtime)
 {
 	struct egroup *eg;
 
@@ -502,6 +503,7 @@ static int __metricgroup__add_metric(struct strbuf *events,
 	eg->metric_expr = pe->metric_expr;
 	eg->metric_unit = pe->unit;
 	eg->runtime = runtime;
+	eg->has_constraint = metricgroup__has_constraint(pe);
 
 	if (expr__find_other(pe->metric_expr, NULL, &eg->pctx, runtime) < 0) {
 		expr__ctx_clear(&eg->pctx);
@@ -509,14 +511,6 @@ static int __metricgroup__add_metric(struct strbuf *events,
 		return -EINVAL;
 	}
 
-	if (events->len > 0)
-		strbuf_addf(events, ",");
-
-	if (metricgroup__has_constraint(pe))
-		metricgroup__add_metric_non_group(events, &eg->pctx);
-	else
-		metricgroup__add_metric_weak_group(events, &eg->pctx);
-
 	list_add_tail(&eg->nd, group_list);
 
 	return 0;
@@ -527,6 +521,7 @@ static int metricgroup__add_metric(const char *metric, struct strbuf *events,
 {
 	struct pmu_events_map *map = perf_pmu__find_map(NULL);
 	struct pmu_event *pe;
+	struct egroup *eg;
 	int i, ret;
 	bool has_match = false;
 
@@ -550,7 +545,8 @@ static int metricgroup__add_metric(const char *metric, struct strbuf *events,
 			pr_debug("metric expr %s for %s\n", pe->metric_expr, pe->metric_name);
 
 			if (!strstr(pe->metric_expr, "?")) {
-				ret = __metricgroup__add_metric(events, group_list, pe, 1);
+				ret = __metricgroup__add_metric(group_list,
+								pe, 1);
 				if (ret)
 					return ret;
 			} else {
@@ -564,13 +560,26 @@ static int metricgroup__add_metric(const char *metric, struct strbuf *events,
 				 */
 
 				for (j = 0; j < count; j++) {
-					ret = __metricgroup__add_metric(events, group_list, pe, j);
+					ret = __metricgroup__add_metric(
+						group_list, pe, j);
 					if (ret)
 						return ret;
 				}
 			}
 		}
 	}
+	list_for_each_entry(eg, group_list, nd) {
+		if (events->len > 0)
+			strbuf_addf(events, ",");
+
+		if (eg->has_constraint) {
+			metricgroup__add_metric_non_group(events,
+							  &eg->pctx);
+		} else {
+			metricgroup__add_metric_weak_group(events,
+							   &eg->pctx);
+		}
+	}
 	return 0;
 }