Commit 5ff0cfc6 authored Nov 09, 2009 by Hitoshi Mitake Committed by Ingo Molnar Nov 09, 2009

perf bench: Fix bench/sched-pipe.c to wait for child process



Ingo reported this small 'perf bench sched pipe' output problem:

 | $ ./perf bench sched pipe
 | (executing 1000000 pipe operations between two tasks)
 |
 |	Total time:4.898 sec
 | $		4.898586 usecs/op
 |		204140 ops/sec
 |
 | the shell prompt came back before the usecs/op and ops/sec line
 | was printed. Process teardown race, lack of wait() or so?

This caused by lack of calling waitpid() by parent process,
so I added it.

Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Kosina <jkosina@suse.cz>
LKML-Reference: <1257737465-7546-1-git-send-email-mitake@dcl.info.waseda.ac.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent bfde82ef

tools/perf/bench/sched-pipe.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -26,6 +26,7 @@
		#include <errno.h>
		#include <assert.h>
		#include <sys/time.h>
		#include <sys/types.h>

		#define LOOPS_DEFAULT 1000000
		static int loops = LOOPS_DEFAULT;
		@@ -58,8 +59,8 @@ int bench_sched_pipe(int argc, const char **argv,
		* discarding returned value of read(), write()
		* causes error in building environment for perf
		*/
		int ret;
		pid_t pid;
		int ret, wait_stat;
		pid_t pid, retpid;

		argc = parse_options(argc, argv, options,
		bench_sched_pipe_usage, 0);
		@@ -87,8 +88,11 @@ int bench_sched_pipe(int argc, const char **argv,
		gettimeofday(&stop, NULL);
		timersub(&stop, &start, &diff);

		if (pid)
		if (pid) {
		retpid = waitpid(pid, &wait_stat, 0);
		assert((retpid == pid) && WIFEXITED(wait_stat));
		return 0;
		}

		if (simple)
		printf("%lu.%03lu\n",