From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755130Ab3AHJjf (ORCPT ); Tue, 8 Jan 2013 04:39:35 -0500 Received: from LGEMRELSE1Q.lge.com ([156.147.1.111]:42067 "EHLO LGEMRELSE1Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754691Ab3AHJjc (ORCPT ); Tue, 8 Jan 2013 04:39:32 -0500 X-AuditID: 9c93016f-b7b54ae000000e9e-0d-50ebe9525312 From: Namhyung Kim To: Arnaldo Carvalho de Melo Cc: Peter Zijlstra , Paul Mackerras , Ingo Molnar , LKML , Namhyung Kim , Hitoshi Mitake Subject: [PATCH] perf bench: Flush stdout before starting bench suite Date: Tue, 8 Jan 2013 18:39:26 +0900 Message-Id: <1357637966-8216-1-git-send-email-namhyung@kernel.org> X-Mailer: git-send-email 1.7.11.7 X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Namhyung Kim perf bench prints header message for bench suite before starting the benchmark. However if the stdout is redirected to a file and bench suite forks child processes this (and possibly other debugging messages too) will be repeated multiple times. $ perf bench sched messaging # Running sched/messaging benchmark... # 20 sender and receiver processes per group # 10 groups == 400 processes run Total time: 0.100 [sec] $ perf bench sched messaging > result.txt $ wc -l result.txt 391 In this file, there were so many "Running sched/messaging benchmark..." lines. This was because stdout is converted to fully-buffered due to the redirection and inherited child processes. Other lines are printed after reaping all those tasks. So fix it by flushing stdout before starting bench suites. Cc: Hitoshi Mitake Signed-off-by: Namhyung Kim --- tools/perf/builtin-bench.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/perf/builtin-bench.c b/tools/perf/builtin-bench.c index cae9a5fd2ecf..afd1255a632f 100644 --- a/tools/perf/builtin-bench.c +++ b/tools/perf/builtin-bench.c @@ -159,6 +159,7 @@ static void all_suite(struct bench_subsys *subsys) /* FROM HERE */ printf("# Running %s/%s benchmark...\n", subsys->name, suites[i].name); + fflush(stdout); argv[1] = suites[i].name; suites[i].fn(1, argv, NULL); @@ -225,6 +226,7 @@ int cmd_bench(int argc, const char **argv, const char *prefix __maybe_unused) printf("# Running %s/%s benchmark...\n", subsystems[i].name, subsystems[i].suites[j].name); + fflush(stdout); status = subsystems[i].suites[j].fn(argc - 1, argv + 1, prefix); goto end; -- 1.7.11.7