[PATCH 08/21] perf hists: Sort hist entries by accumulated period

[Namhyung Kim <namhyung@kernel.org>]

From: Namhyung Kim <namhyung.kim@lge.com>

When callchain accumulation is requested, we need to sort the entries
by accumulated period value.  When accumulated periods of two entries
are same (i.e. single path callchain) put the caller above since
accumulation tends to put callers on higher position for obvious
reason.

Cc: Arun Sharma <asharma@fb.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/builtin-report.c |  6 ++++++
 tools/perf/util/hist.c      | 12 ++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 1314841ffad1..ae298ae91a47 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -509,6 +509,12 @@ iter_add_next_cumulative_entry(struct add_entry_iter *iter,
 
 	he_cache[iter->curr++] = he;
 
+	/*
+	 * This is for putting parents upward during output resort iff
+	 * only a child gets sampled.  See hist_entry__sort_on_period().
+	 */
+	he->callchain->max_depth = callchain_cursor.nr - callchain_cursor.pos;
+
 	return hist_entry__inc_addr_samples(he, evsel->idx, al->addr);
 }
 
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 9a522a05b937..34bbff92b3d7 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -625,6 +625,18 @@ static int hist_entry__sort_on_period(struct hist_entry *a,
 	struct hist_entry *pair;
 	u64 *periods_a, *periods_b;
 
+	if (symbol_conf.cumulate_callchain) {
+		/*
+		 * Put caller above callee when they have equal period.
+		 */
+		if (a->stat_acc->period != b->stat_acc->period)
+			return a->stat_acc->period > b->stat_acc->period ? 1 : -1;
+
+		if (a->callchain->max_depth != b->callchain->max_depth)
+			return a->callchain->max_depth < b->callchain->max_depth ?
+				1 : -1;
+	}
+
 	ret = period_cmp(a->stat.period, b->stat.period);
 	if (ret || !symbol_conf.event_group)
 		return ret;
-- 
1.7.11.7