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 <namhyung@kernel.org>
Acked-by: Hitoshi Mitake <h.mitake@gmail.com>
Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1357637966-8216-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
1 file changed