Commit 45528f7c authored May 25, 2013 by David Ahern Committed by Arnaldo Carvalho de Melo May 28, 2013

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>

parent 6ca5f308

tools/perf/util/stat.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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);

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