[RFC PATCH 5/7] perf metricgroup: delay events string creation

[Ian Rogers <irogers@google.com>]

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>
---
 tools/perf/util/metricgroup.c | 38 +++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 13 deletions(-)

diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
index 48d0143b4b0c..0a00c0f87872 100644
--- a/tools/perf/util/metricgroup.c
+++ b/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,
@@ -496,8 +497,8 @@ 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;
 
@@ -510,6 +511,7 @@ 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);
@@ -517,14 +519,6 @@ 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;
@@ -535,6 +529,7 @@ 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 = -EINVAL;
 
 	if (!map)
@@ -553,7 +548,8 @@ 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);
 			} else {
 				int j, count;
 
@@ -564,13 +560,29 @@ static int metricgroup__add_metric(const char *metric, struct strbuf *events,
 				 * those events to group_list.
 				 */
 
-				for (j = 0; j < count; j++)
-					ret = __metricgroup__add_metric(events, group_list, pe, j);
+				for (j = 0; j < count; j++) {
+					ret = __metricgroup__add_metric(
+						group_list, pe, j);
+				}
 			}
 			if (ret == -ENOMEM)
 				break;
 		}
 	}
+	if (!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 ret;
 }
 
-- 
2.26.2.526.g744177e7f7-goog