From: Namhyung Kim Date: Tue, 8 Jan 2013 09:39:26 +0000 (+0900) Subject: perf bench: Flush stdout before starting bench suite X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=9b494ea2f5638184bc203a30062b32b9a9a05d9e;p=openwrt%2Fstaging%2Fblogic.git perf bench: Flush stdout before starting bench suite 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. Signed-off-by: Namhyung Kim Acked-by: Hitoshi Mitake Cc: Hitoshi Mitake Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1357637966-8216-1-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- 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;