Messages in this thread | | | Date | Fri, 4 Jan 2019 13:54:41 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH] perf stat: Poll for monitored tasks being alive in fork mode |
| |
On Fri, Jan 04, 2019 at 10:28:17AM +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. > > Signed-off-by: Jin Yao <yao.jin@linux.intel.com> > --- > tools/perf/builtin-stat.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c > index 63a3afc..71f3bc8 100644 > --- a/tools/perf/builtin-stat.c > +++ b/tools/perf/builtin-stat.c > @@ -553,6 +553,13 @@ 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) && > + (child_pid != -1)) {
do we need that child_pid check? we just returned from waitpid so we should be ok.. we just make the race window smaller
could we just do:
if (!is_target_alive(&target, evsel_list->threads)) { kill(child_pid, SIGTERM); break; }
also I'm not sure we should do this only under new option, as it might break people's scripts.. thoughts?
jirka
> + kill(child_pid, SIGTERM); > + break; > + } > + > nanosleep(&ts, NULL); > if (timeout) > break; > -- > 2.7.4 >
| |