Hi Arnaldo,
Is this patch acceptable?
Thanks
Jin Yao
On 1/7/2019 5:05 PM, Jiri Olsa wrote:
On Mon, Jan 07, 2019 at 09:00:50AM +0800, Jin Yao wrote:
Following test shows the stat keeps running even if no longer
task to monitor (mgen exits at ~5s).
perf stat -e cycles -p `pgrep mgen` -I1000 -- sleep 10
time counts unit events
1.000148916 1,308,365,864 cycles
2.000379171 1,297,269,875 cycles
3.000556719 1,297,187,078 cycles
4.000914241 761,261,827 cycles
5.001306091 <not counted> cycles
6.001676881 <not counted> cycles
7.002046336 <not counted> cycles
8.002405651 <not counted> cycles
9.002766625 <not counted> cycles
10.001395827 <not counted> cycles
We'd better finish stat immediately if there's no longer task to
monitor.
After:
perf stat -e cycles -p `pgrep mgen` -I1000 -- sleep 10
time counts unit events
1.000180062 1,236,592,661 cycles
2.000421539 1,223,733,572 cycles
3.000609910 1,297,047,663 cycles
4.000807545 1,297,215,816 cycles
5.001001578 1,297,208,032 cycles
6.001390345 582,343,659 cycles
sleep: Terminated
Now the stat exits immediately when the monitored tasks ends.
v2:
---
There is a potential race condition window, that is the
child_pid set with -1 and kill(-1, SIGTERM) may happen.
Jiri provides a simple method which stores the child_pid to
a local variable and check the local variable before kill().
At least, we can avoid the kill(-1, SIGTERM) case.
Signed-off-by: Jin Yao <yao....@linux.intel.com>
Reviewed-by: Jiri Olsa <jo...@kernel.org>
thanks,
jirka
---
tools/perf/builtin-stat.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 63a3afc..bd5fb8e 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -553,6 +553,15 @@ static int __run_perf_stat(int argc, const char **argv,
int run_idx)
if (interval || timeout) {
while (!waitpid(child_pid, &status, WNOHANG)) {
+ if (!is_target_alive(&target,
+ evsel_list->threads)) {
+ int pid = child_pid;
+
+ if (pid != -1)
+ kill(pid, SIGTERM);
+ break;
+ }
+
nanosleep(&ts, NULL);
if (timeout)
break;
--
2.7.4
