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SubjectRe: [PATCH] perf bench: Flush stdout before starting bench suite
At Tue,  8 Jan 2013 18:39:26 +0900,
Namhyung Kim wrote:
>
> From: Namhyung Kim <namhyung.kim@lge.com>
>
> 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.

Thanks a lot, I couldn't notice this problem.

Acked-by: Hitoshi Mitake <h.mitake@gmail.com>

>
> Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
> 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
>
>


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