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| author | David Ahern <dsahern@gmail.com> | 2013-05-26 04:24:48 +0400 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2013-05-28 17:24:04 +0400 |
| commit | 45528f7c699a71d2f3096173980aadd43dff6eaa (patch) | |
| tree | 88090f64f8729195ad68386d3693be18a8102dd3 | |
| parent | 6ca5f3081f903e2b25e58a061ddad486f846561e (diff) | |
| download | linux-45528f7c699a71d2f3096173980aadd43dff6eaa.tar.xz | |
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>
| -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 23742126f47c..7c59c28afcc5 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); |