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

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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>
This commit is contained in:
Hitoshi Mitake 2009-11-09 12:31:05 +09:00 committed by Ingo Molnar
parent bfde82ef51
commit 5ff0cfc67f
1 changed files with 7 additions and 3 deletions
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10
tools/perf/bench/sched-pipe.c
View file

@ -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",