[PATCH v1 3/4] perf stat: Fix group lookup for metric group

[Andi Kleen]

From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

The metric group code tries to find a group it added earlier
in the evlist. Fix the lookup to handle groups with partially
overlaps correctly. When a sub string match fails and we reset
the match, we have to compare the first element again.

I also renamed the find_evsel function to find_evsel_group
to make its purpose clearer.

With the earlier changes this fixes:

Before:

% perf stat -M UPI,IPC sleep 1
...
         1,032,922      uops_retired.retire_slots #      1.1 UPI
         1,896,096      inst_retired.any
         1,896,096      inst_retired.any
         1,177,254      cpu_clk_unhalted.thread

After:

% perf stat -M UPI,IPC sleep 1
...
        1,013,193      uops_retired.retire_slots #      1.1 UPI
           932,033      inst_retired.any
           932,033      inst_retired.any          #      0.9 IPC
         1,091,245      cpu_clk_unhalted.thread

Fixes: b18f3e365019 ("perf stat: Support JSON metrics ...")
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
 tools/perf/util/metricgroup.c | 47 ++++++++++++++++++++++++++---------
 1 file changed, 35 insertions(+), 12 deletions(-)

diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
index 699e020737d9..fabdb6dde88e 100644
--- a/tools/perf/util/metricgroup.c
+++ b/tools/perf/util/metricgroup.c
@@ -85,26 +85,49 @@ struct egroup {
 	const char *metric_expr;
 };
 
-static struct perf_evsel *find_evsel(struct perf_evlist *perf_evlist,
-				     const char **ids,
-				     int idnum,
-				     struct perf_evsel **metric_events)
+static bool record_evsel(int *ind, struct perf_evsel **start,
+			 int idnum,
+			 struct perf_evsel **metric_events,
+			 struct perf_evsel *ev)
+{
+	metric_events[*ind] = ev;
+	if (*ind == 0)
+		*start = ev;
+	if (++*ind == idnum) {
+		metric_events[*ind] = NULL;
+		return true;
+	}
+	return false;
+}
+
+static struct perf_evsel *find_evsel_group(struct perf_evlist *perf_evlist,
+					   const char **ids,
+					   int idnum,
+					   struct perf_evsel **metric_events)
 {
 	struct perf_evsel *ev, *start = NULL;
 	int ind = 0;
 
 	evlist__for_each_entry (perf_evlist, ev) {
+		if (ev->collect_stat)
+			continue;
 		if (!strcmp(ev->name, ids[ind])) {
-			metric_events[ind] = ev;
-			if (ind == 0)
-				start = ev;
-			if (++ind == idnum) {
-				metric_events[ind] = NULL;
+			if (record_evsel(&ind, &start, idnum,
+					 metric_events, ev))
 				return start;
-			}
 		} else {
+			/*
+			 * We saw some other event that is not
+			 * in our list of events. Discard
+			 * the whole match and start again.
+			 */
 			ind = 0;
 			start = NULL;
+			if (!strcmp(ev->name, ids[ind])) {
+				if (record_evsel(&ind, &start, idnum,
+						 metric_events, ev))
+					return start;
+			}
 		}
 	}
 	/*
@@ -134,8 +157,8 @@ static int metricgroup__setup_events(struct list_head *groups,
 			ret = -ENOMEM;
 			break;
 		}
-		evsel = find_evsel(perf_evlist, eg->ids, eg->idnum,
-				   metric_events);
+		evsel = find_evsel_group(perf_evlist, eg->ids, eg->idnum,
+					 metric_events);
 		if (!evsel) {
 			pr_debug("Cannot resolve %s: %s\n",
 					eg->metric_name, eg->metric_expr);
-- 
2.20.1