From 5ff0cfc67f00fe0feaa1da0b2359232ea4aa0ee7 Mon Sep 17 00:00:00 2001 From: Hitoshi Mitake Date: Mon, 9 Nov 2009 12:31:05 +0900 Subject: [PATCH] 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 Cc: Rusty Russell Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Mike Galbraith Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: Jiri Kosina LKML-Reference: <1257737465-7546-1-git-send-email-mitake@dcl.info.waseda.ac.jp> Signed-off-by: Ingo Molnar --- tools/perf/bench/sched-pipe.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/tools/perf/bench/sched-pipe.c b/tools/perf/bench/sched-pipe.c index 3214ed20b1aa..6a29100e9282 100644 --- a/tools/perf/bench/sched-pipe.c +++ b/tools/perf/bench/sched-pipe.c @@ -26,6 +26,7 @@ #include #include #include +#include #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",