From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755367Ab3EaLv4 (ORCPT ); Fri, 31 May 2013 07:51:56 -0400 Received: from terminus.zytor.com ([198.137.202.10]:56985 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751489Ab3EaLvr (ORCPT ); Fri, 31 May 2013 07:51:47 -0400 Date: Fri, 31 May 2013 04:51:11 -0700 From: tip-bot for David Ahern Message-ID: Cc: acme@redhat.com, linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, peterz@infradead.org, namhyung@kernel.org, runzhen@linux.vnet.ibm.com, jolsa@redhat.com, fweisbec@gmail.com, xiaoguangrong@linux.vnet.ibm.com, dsahern@gmail.com, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, acme@redhat.com, peterz@infradead.org, namhyung@kernel.org, jolsa@redhat.com, runzhen@linux.vnet.ibm.com, fweisbec@gmail.com, xiaoguangrong@linux.vnet.ibm.com, dsahern@gmail.com, tglx@linutronix.de In-Reply-To: <1369527896-3650-9-git-send-email-dsahern@gmail.com> References: <1369527896-3650-9-git-send-email-dsahern@gmail.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf stats: Fix divide by 0 in variance Git-Commit-ID: 45528f7c699a71d2f3096173980aadd43dff6eaa X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 45528f7c699a71d2f3096173980aadd43dff6eaa Gitweb: http://git.kernel.org/tip/45528f7c699a71d2f3096173980aadd43dff6eaa Author: David Ahern AuthorDate: Sat, 25 May 2013 18:24:48 -0600 Committer: Arnaldo Carvalho de Melo CommitDate: Tue, 28 May 2013 16:24:04 +0300 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 Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Runzhen Wang Cc: Xiao Guangrong Link: http://lkml.kernel.org/r/1369527896-3650-9-git-send-email-dsahern@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/stat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c index 2374212..7c59c28 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);