From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752190AbaJATvS (ORCPT ); Wed, 1 Oct 2014 15:51:18 -0400 Received: from mail.kernel.org ([198.145.19.201]:47794 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750945AbaJATvO (ORCPT ); Wed, 1 Oct 2014 15:51:14 -0400 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Davidlohr Bueso , Davidlohr Bueso , Arnaldo Carvalho de Melo Subject: [PATCH 4/8] perf bench futex: Sanitize -q option in requeue Date: Wed, 1 Oct 2014 16:50:39 -0300 Message-Id: <1412193043-15493-5-git-send-email-acme@kernel.org> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1412193043-15493-1-git-send-email-acme@kernel.org> References: <1412193043-15493-1-git-send-email-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Davidlohr Bueso When given the number of threads to requeue at once by user input, there's always the risk of this value being larger than the total number of threads. This doesn't make any sense, and the kernel can easily deal with such sort of situations, hence no big deal. We should however prevent bogus output such as: ./perf bench --repeat 2 futex requeue -q 10 Run summary [PID 22210]: Requeuing 4 threads (from [private] 0x99ef3c to 0x99ef38), 10 at a time. [Run 1]: Requeued 10 of 4 threads in 0.0040 ms [Run 2]: Requeued 10 of 4 threads in 0.0030 ms Requeued 10 of 4 threads in 0.0035 ms (+-14.29%) Signed-off-by: Davidlohr Bueso Cc: Davidlohr Bueso Link: http://lkml.kernel.org/r/1412008868-22328-2-git-send-email-dave@stgolabs.net Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/bench/futex-requeue.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/perf/bench/futex-requeue.c b/tools/perf/bench/futex-requeue.c index 9837a8831406..bedff6b5b3cf 100644 --- a/tools/perf/bench/futex-requeue.c +++ b/tools/perf/bench/futex-requeue.c @@ -172,6 +172,9 @@ int bench_futex_requeue(int argc, const char **argv, gettimeofday(&end, NULL); timersub(&end, &start, &runtime); + if (nrequeued > nthreads) + nrequeued = nthreads; + update_stats(&requeued_stats, nrequeued); update_stats(&requeuetime_stats, runtime.tv_usec); @@ -190,7 +193,6 @@ int bench_futex_requeue(int argc, const char **argv, if (ret) err(EXIT_FAILURE, "pthread_join"); } - } /* cleanup & report results */ -- 1.9.3