perf streams: Calculate the sum of total streams hits

We have used callchain_node->hit to measure the hot level of one stream.
This patch calculates the sum of hits of total streams.

Thus in next patch, we can use following formula to report hot percent
for one stream.

hot percent = callchain_node->hit / sum of total hits

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20201009022845.13141-6-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/callchain.c

@@ -1667,3 +1667,35 @@ bool callchain_cnode_matched(struct callchain_node *base_cnode,
 
 	return match;
 }
+
+static u64 count_callchain_hits(struct hist_entry *he)
+{
+	struct rb_root *root = &he->sorted_chain;
+	struct rb_node *rb_node = rb_first(root);
+	struct callchain_node *node;
+	u64 chain_hits = 0;
+
+	while (rb_node) {
+		node = rb_entry(rb_node, struct callchain_node, rb_node);
+		chain_hits += node->hit;
+		rb_node = rb_next(rb_node);
+	}
+
+	return chain_hits;
+}
+
+u64 callchain_total_hits(struct hists *hists)
+{
+	struct rb_node *next = rb_first_cached(&hists->entries);
+	u64 chain_hits = 0;
+
+	while (next) {
+		struct hist_entry *he = rb_entry(next, struct hist_entry,
+						 rb_node);
+
+		chain_hits += count_callchain_hits(he);
+		next = rb_next(&he->rb_node);
+	}
+
+	return chain_hits;
+}

tools/perf/util/callchain.h

@@ -13,6 +13,7 @@ struct ip_callchain;
 struct map;
 struct perf_sample;
 struct thread;
+struct hists;
 
 #define HELP_PAD "\t\t\t\t"
 
@@ -302,4 +303,6 @@ void callchain_param_setup(u64 sample_type);
 bool callchain_cnode_matched(struct callchain_node *base_cnode,
 			     struct callchain_node *pair_cnode);
 
+u64 callchain_total_hits(struct hists *hists);
+
 #endif	/* __PERF_CALLCHAIN_H */

tools/perf/util/stream.c

@@ -121,6 +121,8 @@ static void init_hot_callchain(struct hists *hists, struct evsel_streams *es)
 		update_hot_callchain(he, es);
 		next = rb_next(&he->rb_node);
 	}
+
+	es->streams_hits = callchain_total_hits(hists);
 }
 
 static int evlist__init_callchain_streams(struct evlist *evlist,

tools/perf/util/stream.h

@@ -14,6 +14,7 @@ struct evsel_streams {
 	int			nr_streams_max;
 	int			nr_streams;
 	int			evsel_idx;
+	u64			streams_hits;
 };
 
 struct evlist_streams {