linux-kernel - [tip:perf/urgent] perf stat: Initialize statistics correctly

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Message-ID: <tip-90f6bb6c98ffef42125d7be6d4612505f561fbce@git.kernel.org>
Date:	Mon, 14 Apr 2014 07:54:17 -0700
From:	tip-bot for Andi Kleen <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
	ak@...ux.intel.com, tglx@...utronix.de, namhyung@...nel.org,
	jolsa@...hat.com
Subject: [tip:perf/urgent] perf stat: Initialize statistics correctly

Commit-ID:  90f6bb6c98ffef42125d7be6d4612505f561fbce
Gitweb:     http://git.kernel.org/tip/90f6bb6c98ffef42125d7be6d4612505f561fbce
Author:     Andi Kleen <ak@...ux.intel.com>
AuthorDate: Tue, 25 Mar 2014 10:31:38 -0700
Committer:  Jiri Olsa <jolsa@...hat.com>
CommitDate: Mon, 14 Apr 2014 12:56:06 +0200

perf stat: Initialize statistics correctly

perf stat did initialize the stats structure used to compute
stddev etc. incorrectly. It merely zeroes it. But one member
(min) needs to be set to a non zero value. This causes min
to be not computed at all. Call init_stats() correctly.

It doesn't matter for stat currently because it doesn't use
min, but it's still better to do it correctly.

The other users of statistics are already correct.

Signed-off-by: Andi Kleen <ak@...ux.intel.com>
Acked-by: Namhyung Kim <namhyung@...nel.org>
Link: http://lkml.kernel.org/r/1395768699-16060-1-git-send-email-andi@firstfloor.org
Signed-off-by: Jiri Olsa <jolsa@...hat.com>
---
 tools/perf/builtin-stat.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 8b0e1c9..65a151e 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -174,13 +174,20 @@ static inline int perf_evsel__nr_cpus(struct perf_evsel *evsel)
 
 static void perf_evsel__reset_stat_priv(struct perf_evsel *evsel)
 {
-	memset(evsel->priv, 0, sizeof(struct perf_stat));
+	int i;
+	struct perf_stat *ps = evsel->priv;
+
+	for (i = 0; i < 3; i++)
+		init_stats(&ps->res_stats[i]);
 }
 
 static int perf_evsel__alloc_stat_priv(struct perf_evsel *evsel)
 {
 	evsel->priv = zalloc(sizeof(struct perf_stat));
-	return evsel->priv == NULL ? -ENOMEM : 0;
+	if (evsel == NULL)
+		return -ENOMEM;
+	perf_evsel__reset_stat_priv(evsel);
+	return 0;
 }
 
 static void perf_evsel__free_stat_priv(struct perf_evsel *evsel)
--
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