perf streams: Report hot streams

We show the streams separately. They are divided into different sections.

1. "Matched hot streams"

2. "Hot streams in old perf data only"

3. "Hot streams in new perf data only".

For each stream, we report the cycles and hot percent (hits%).

For example,

     cycles: 2, hits: 4.08%
 --------------------------
              main div.c:42
      compute_flag div.c:28

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20201009022845.13141-7-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/callchain.c

@@ -1699,3 +1699,16 @@ u64 callchain_total_hits(struct hists *hists)
 
 	return chain_hits;
 }
+
+s64 callchain_avg_cycles(struct callchain_node *cnode)
+{
+	struct callchain_list *chain;
+	s64 cycles = 0;
+
+	list_for_each_entry(chain, &cnode->val, list) {
+		if (chain->srcline && chain->branch_count)
+			cycles += chain->cycles_count / chain->branch_count;
+	}
+
+	return cycles;
+}

tools/perf/util/callchain.h

@@ -305,4 +305,6 @@ bool callchain_cnode_matched(struct callchain_node *base_cnode,
 
 u64 callchain_total_hits(struct hists *hists);
 
+s64 callchain_avg_cycles(struct callchain_node *cnode);
+
 #endif	/* __PERF_CALLCHAIN_H */

tools/perf/util/stream.c

@@ -217,3 +217,126 @@ void evsel_streams__match(struct evsel_streams *es_base,
 			stream__link(base_stream, pair_stream);
 	}
 }
+
+static void print_callchain_pair(struct stream *base_stream, int idx,
+				 struct evsel_streams *es_base,
+				 struct evsel_streams *es_pair)
+{
+	struct callchain_node *base_cnode = base_stream->cnode;
+	struct callchain_node *pair_cnode = base_stream->pair_cnode;
+	struct callchain_list *base_chain, *pair_chain;
+	char buf1[512], buf2[512], cbuf1[256], cbuf2[256];
+	char *s1, *s2;
+	double pct;
+
+	printf("\nhot chain pair %d:\n", idx);
+
+	pct = (double)base_cnode->hit / (double)es_base->streams_hits;
+	scnprintf(buf1, sizeof(buf1), "cycles: %ld, hits: %.2f%%",
+		  callchain_avg_cycles(base_cnode), pct * 100.0);
+
+	pct = (double)pair_cnode->hit / (double)es_pair->streams_hits;
+	scnprintf(buf2, sizeof(buf2), "cycles: %ld, hits: %.2f%%",
+		  callchain_avg_cycles(pair_cnode), pct * 100.0);
+
+	printf("%35s\t%35s\n", buf1, buf2);
+
+	printf("%35s\t%35s\n",
+	       "---------------------------",
+	       "--------------------------");
+
+	pair_chain = list_first_entry(&pair_cnode->val,
+				      struct callchain_list,
+				      list);
+
+	list_for_each_entry(base_chain, &base_cnode->val, list) {
+		if (&pair_chain->list == &pair_cnode->val)
+			return;
+
+		s1 = callchain_list__sym_name(base_chain, cbuf1, sizeof(cbuf1),
+					      false);
+		s2 = callchain_list__sym_name(pair_chain, cbuf2, sizeof(cbuf2),
+					      false);
+
+		scnprintf(buf1, sizeof(buf1), "%35s\t%35s", s1, s2);
+		printf("%s\n", buf1);
+		pair_chain = list_next_entry(pair_chain, list);
+	}
+}
+
+static void print_stream_callchain(struct stream *stream, int idx,
+				   struct evsel_streams *es, bool pair)
+{
+	struct callchain_node *cnode = stream->cnode;
+	struct callchain_list *chain;
+	char buf[512], cbuf[256], *s;
+	double pct;
+
+	printf("\nhot chain %d:\n", idx);
+
+	pct = (double)cnode->hit / (double)es->streams_hits;
+	scnprintf(buf, sizeof(buf), "cycles: %ld, hits: %.2f%%",
+		  callchain_avg_cycles(cnode), pct * 100.0);
+
+	if (pair) {
+		printf("%35s\t%35s\n", "", buf);
+		printf("%35s\t%35s\n",
+		       "", "--------------------------");
+	} else {
+		printf("%35s\n", buf);
+		printf("%35s\n", "--------------------------");
+	}
+
+	list_for_each_entry(chain, &cnode->val, list) {
+		s = callchain_list__sym_name(chain, cbuf, sizeof(cbuf), false);
+
+		if (pair)
+			scnprintf(buf, sizeof(buf), "%35s\t%35s", "", s);
+		else
+			scnprintf(buf, sizeof(buf), "%35s", s);
+
+		printf("%s\n", buf);
+	}
+}
+
+static void callchain_streams_report(struct evsel_streams *es_base,
+				     struct evsel_streams *es_pair)
+{
+	struct stream *base_stream;
+	int i, idx = 0;
+
+	printf("[ Matched hot streams ]\n");
+	for (i = 0; i < es_base->nr_streams; i++) {
+		base_stream = &es_base->streams[i];
+		if (base_stream->pair_cnode) {
+			print_callchain_pair(base_stream, ++idx,
+					     es_base, es_pair);
+		}
+	}
+
+	idx = 0;
+	printf("\n[ Hot streams in old perf data only ]\n");
+	for (i = 0; i < es_base->nr_streams; i++) {
+		base_stream = &es_base->streams[i];
+		if (!base_stream->pair_cnode) {
+			print_stream_callchain(base_stream, ++idx,
+					       es_base, false);
+		}
+	}
+
+	idx = 0;
+	printf("\n[ Hot streams in new perf data only ]\n");
+	for (i = 0; i < es_pair->nr_streams; i++) {
+		base_stream = &es_pair->streams[i];
+		if (!base_stream->pair_cnode) {
+			print_stream_callchain(base_stream, ++idx,
+					       es_pair, true);
+		}
+	}
+}
+
+void evsel_streams__report(struct evsel_streams *es_base,
+			   struct evsel_streams *es_pair)
+{
+	return callchain_streams_report(es_base, es_pair);
+}

tools/perf/util/stream.h

@@ -35,4 +35,7 @@ struct evsel_streams *evsel_streams__entry(struct evlist_streams *els,
 void evsel_streams__match(struct evsel_streams *es_base,
 			  struct evsel_streams *es_pair);
 
+void evsel_streams__report(struct evsel_streams *es_base,
+			   struct evsel_streams *es_pair);
+
 #endif /* __PERF_STREAM_H */