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>
diff --git a/tools/perf/bench/sched-pipe.c b/tools/perf/bench/sched-pipe.c
index 3214ed2..6a29100 100644
--- a/tools/perf/bench/sched-pipe.c
+++ b/tools/perf/bench/sched-pipe.c
@@ -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 @@
* 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 @@
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",