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author | David Ahern <dsahern@gmail.com> | 2013-05-25 18:24:48 -0600 |
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committer | Chanho Park <chanho61.park@samsung.com> | 2014-03-20 17:34:24 +0900 |
commit | 743b38b40f04f285a70451129f5cf1ab20a16443 (patch) | |
tree | 40e0adeb776e0ea73c493939d986253a5727f3f8 /tools | |
parent | 57ad3a9a7b8a73f204a22f66c9cebfc832bc090c (diff) | |
download | linux-3.10-743b38b40f04f285a70451129f5cf1ab20a16443.tar.gz linux-3.10-743b38b40f04f285a70451129f5cf1ab20a16443.tar.bz2 linux-3.10-743b38b40f04f285a70451129f5cf1ab20a16443.zip |
perf stats: Fix divide by 0 in variance
Number of samples needs to be greater 1 to have a variance.
Fixes nan% in perf-kvm-live output.
Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Runzhen Wang <runzhen@linux.vnet.ibm.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1369527896-3650-9-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r-- | tools/perf/util/stat.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c index 23742126f47..7c59c28afcc 100644 --- a/tools/perf/util/stat.c +++ b/tools/perf/util/stat.c @@ -37,7 +37,7 @@ double stddev_stats(struct stats *stats) { double variance, variance_mean; - if (!stats->n) + if (stats->n < 2) return 0.0; variance = stats->M2 / (stats->n - 1); |