[PATCH 2/7] perf diff: Make hist_entry_diff fields union

[Namhyung Kim <namhyung@kernel.org>]

The period_ratio_delta, period_ratio and wdiff are never by used at the
same time.  Instead, Just one of them is accessed according to a
comparison method.  So make it union to reduce memory footprint.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/util/sort.h | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/sort.h b/tools/perf/util/sort.h
index af192f172fa2..de3303fe726d 100644
--- a/tools/perf/util/sort.h
+++ b/tools/perf/util/sort.h
@@ -58,15 +58,16 @@ struct he_stat {
 
 struct hist_entry_diff {
 	bool	computed;
+	union {
+		/* PERF_HPP__DELTA */
+		double	period_ratio_delta;
 
-	/* PERF_HPP__DELTA */
-	double	period_ratio_delta;
-
-	/* PERF_HPP__RATIO */
-	double	period_ratio;
+		/* PERF_HPP__RATIO */
+		double	period_ratio;
 
-	/* HISTC_WEIGHTED_DIFF */
-	s64	wdiff;
+		/* HISTC_WEIGHTED_DIFF */
+		s64	wdiff;
+	};
 };
 
 /**
-- 
2.3.5