perf diff: Start moving to support matching more than two hists

We want to match more than two hists, so that we can match more than two
perf.data files and moreover, match hist_entries (buckets) in multiple
events in a group.

So the "baseline"/"leader" will instead of a ->pair pointer, use a
list_head, that will link to the pairs and hists__match use it.

Following that perf_evlist__link will link the hists in its evsel
groups.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-2kbmzepoi544ygj9godseqpv@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 25 insertions, 4 deletions

diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index a1b823f..f42de79 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -244,6 +244,8 @@ static struct hist_entry *hist_entry__new(struct hist_entry *template)
 			he->ms.map->referenced = true;
 		if (symbol_conf.use_callchain)
 			callchain_init(he->callchain);
+
+		INIT_LIST_HEAD(&he->pairs.node);
 	}
 
 	return he;
diff --git a/tools/perf/util/sort.h b/tools/perf/util/sort.h
index 13761d8..b4e8c3b 100644
--- a/tools/perf/util/sort.h
+++ b/tools/perf/util/sort.h
@@ -77,6 +77,10 @@ struct hist_entry_diff {
 struct hist_entry {
 	struct rb_node		rb_node_in;
 	struct rb_node		rb_node;
+	union {
+		struct list_head node;
+		struct list_head head;
+	} pairs;
 	struct he_stat		stat;
 	struct map_symbol	ms;
 	struct thread		*thread;
@@ -96,15 +100,30 @@ struct hist_entry {
 	char			*srcline;
 	struct symbol		*parent;
 	unsigned long		position;
-	union {
-		struct hist_entry *pair;
-		struct rb_root	  sorted_chain;
-	};
+	struct rb_root		sorted_chain;
 	struct branch_info	*branch_info;
 	struct hists		*hists;
 	struct callchain_root	callchain[0];
 };
 
+static inline bool hist_entry__has_pairs(struct hist_entry *he)
+{
+	return !list_empty(&he->pairs.node);
+}
+
+static inline struct hist_entry *hist_entry__next_pair(struct hist_entry *he)
+{
+	if (hist_entry__has_pairs(he))
+		return list_entry(he->pairs.node.next, struct hist_entry, pairs.node);
+	return NULL;
+}
+
+static inline void hist__entry_add_pair(struct hist_entry *he,
+					struct hist_entry *pair)
+{
+	list_add_tail(&he->pairs.head, &pair->pairs.node);
+}
+
 enum sort_type {
 	SORT_PID,
 	SORT_COMM,