perf streams: Link stream pair

In previous patch, we have created an evsel_streams for one event, and
top N hottest streams will be saved in a stream array in evsel_streams.

This patch compares total streams among two evsel_streams.

Once two streams are fully matched, they will be linked as a pair. From
the pair, we can know which streams are matched.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20201009022845.13141-5-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/stream.c

@@ -175,3 +175,43 @@ struct evsel_streams *evsel_streams__entry(struct evlist_streams *els,
 
 	return NULL;
 }
+
+static struct stream *stream__callchain_match(struct stream *base_stream,
+					      struct evsel_streams *es_pair)
+{
+	for (int i = 0; i < es_pair->nr_streams; i++) {
+		struct stream *pair_stream = &es_pair->streams[i];
+
+		if (callchain_cnode_matched(base_stream->cnode,
+					    pair_stream->cnode)) {
+			return pair_stream;
+		}
+	}
+
+	return NULL;
+}
+
+static struct stream *stream__match(struct stream *base_stream,
+				    struct evsel_streams *es_pair)
+{
+	return stream__callchain_match(base_stream, es_pair);
+}
+
+static void stream__link(struct stream *base_stream, struct stream *pair_stream)
+{
+	base_stream->pair_cnode = pair_stream->cnode;
+	pair_stream->pair_cnode = base_stream->cnode;
+}
+
+void evsel_streams__match(struct evsel_streams *es_base,
+			  struct evsel_streams *es_pair)
+{
+	for (int i = 0; i < es_base->nr_streams; i++) {
+		struct stream *base_stream = &es_base->streams[i];
+		struct stream *pair_stream;
+
+		pair_stream = stream__match(base_stream, es_pair);
+		if (pair_stream)
+			stream__link(base_stream, pair_stream);
+	}
+}

tools/perf/util/stream.h

@@ -6,6 +6,7 @@
 
 struct stream {
 	struct callchain_node	*cnode;
+	struct callchain_node	*pair_cnode;
 };
 
 struct evsel_streams {
@@ -30,4 +31,7 @@ struct evlist_streams *evlist__create_streams(struct evlist *evlist,
 struct evsel_streams *evsel_streams__entry(struct evlist_streams *els,
 					   int evsel_idx);
 
+void evsel_streams__match(struct evsel_streams *es_base,
+			  struct evsel_streams *es_pair);
+
 #endif /* __PERF_STREAM_H */