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Subject[PATCH 1/2] perf, tools, stat: Initialize statistics correctly
Date
From: Andi Kleen <ak@linux.intel.com>

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@linux.intel.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)
--
1.8.5.3


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