On Wed, 04 Apr 2018 10:17:03 -0500 Tom Zanussi <tom.zanu...@linux.intel.com> wrote:
> Hi Masami, > > On Wed, 2018-04-04 at 21:33 +0900, Masami Hiramatsu wrote: > > Hi Tom, > > > > On Mon, 02 Apr 2018 12:09:33 -0500 > > Tom Zanussi <tom.zanu...@linux.intel.com> wrote: > > > > > after: > > > > > > # echo 'wakeup_latency u64 lat; pid_t pid' >> > > > /sys/kernel/debug/tracing/synthetic_events > > > # echo 'hist:keys=pid:ts0=common_timestamp.usecs if comm=="cyclictest"' > > > >> /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger > > > # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0 if > > > next_comm=="cyclictest"' >> > > > /sys/kernel/debug/tracing/events/sched/sched_switch/trigger > > > # echo > > > 'hist:keys=next_pid:onmatch(sched.sched_wakeup).wakeup_latency(sched.sched_switch.$wakeup_lat,next_pid) > > > if next_comm=="cyclictest"' >> > > > /sys/kernel/debug/tracing/events/sched/sched_switch/trigger > > > # echo > > > 'hist:keys=next_pid:onmatch(sched.sched_wakeup).wakeup_latency(sched.sched_switch.$wakeup_lat,prev_pid) > > > if next_comm=="cyclictest"' >> > > > /sys/kernel/debug/tracing/events/sched/sched_switch/trigger > > > # echo 'hist:keys=next_pid if next_comm=="cyclictest"' >> > > > /sys/kernel/debug/tracing/events/sched/sched_switch/trigger > > > > I ensured this sequence has no problem. > > After above sequence, the trigger file shows > > > > ====== > > # cat events/sched/sched_switch/trigger > > hist:keys=next_pid:vals=hitcount:wakeup_lat=common_timestamp.usecs-$ts0:sort=hitcount:size=2048:clock=global > > if next_comm=="cyclictest" [active] > > hist:keys=next_pid:vals=hitcount:sort=hitcount:size=2048:onmatch(sched.sched_wakeup).wakeup_latency(sched.sched_switch.$wakeup_lat,next_pid) > > if next_comm=="cyclictest" [active] > > hist:keys=next_pid:vals=hitcount:sort=hitcount:size=2048:onmatch(sched.sched_wakeup).wakeup_latency(sched.sched_switch.$wakeup_lat,prev_pid) > > if next_comm=="cyclictest" [active] > > hist:keys=next_pid:vals=hitcount:sort=hitcount:size=2048 if > > next_comm=="cyclictest" [active] > > ====== > > > > So I clear the last one > > > > ====== > > # echo '!hist:keys=next_pid if next_comm=="cyclictest"' >> > > events/sched/sched_switch/trigger > > # > > ====== > > > > OK, it should be removed. I can not see it anymore on the trigger file. > > > > ====== > > # cat events/sched/sched_switch/trigger > > hist:keys=next_pid:vals=hitcount:wakeup_lat=common_timestamp.usecs-$ts0:sort=hitcount:size=2048:clock=global > > if next_comm=="cyclictest" [active] > > hist:keys=next_pid:vals=hitcount:sort=hitcount:size=2048:onmatch(sched.sched_wakeup).wakeup_latency(sched.sched_switch.$wakeup_lat,next_pid) > > if next_comm=="cyclictest" [active] > > hist:keys=next_pid:vals=hitcount:sort=hitcount:size=2048:onmatch(sched.sched_wakeup).wakeup_latency(sched.sched_switch.$wakeup_lat,prev_pid) > > if next_comm=="cyclictest" [active] > > ====== > > > > But when I missed to remove it again, it is accepted (is not an error?) > > > > ====== > > # echo '!hist:keys=next_pid if next_comm=="cyclictest"' >> > > events/sched/sched_switch/trigger > > # > > ====== > > This is consistent with existing behavior, not only for the hist > triggers but ftrace in general I think e.g. > > # echo 'traceoff:1 if nr_rq > 1' >> > /sys/kernel/debug/tracing/events/block/block_unplug/trigger > # echo '!traceoff:1 if nr_rq > 1' >> > /sys/kernel/debug/tracing/events/block/block_unplug/trigger > # echo '!traceoff:1 if nr_rq > 1' >> > /sys/kernel/debug/tracing/events/block/block_unplug/trigger > > # echo 'try_to_wake_up:enable_event:sched:sched_switch:2' >> set_ftrace_filter > # echo '!try_to_wake_up:enable_event:sched:sched_switch:2' >> > set_ftrace_filter > # echo '!try_to_wake_up:enable_event:sched:sched_switch:2' >> > set_ftrace_filter > > Neither produces an error trying to remove an already-removed trigger. > Or are you thinking about something else? Hmm, OK, it is ftrace's behavior. > > Hmm... anyway, let's clear others too. > > > > ====== > > # echo > > '!hist:keys=next_pid:onmatch(sched.sched_wakeup).wakeup_latency(sched.sched_switch.$wakeup_lat,next_pid) > > if next_comm=="cyclictest"' >> events/sched/sched_switch/trigger > > # echo > > '!hist:keys=next_pid:onmatch(sched.sched_wakeup).wakeup_latency(sched.sched_switch.$wakeup_lat,prev_pid) > > if next_comm=="cyclictest"' >> events/sched/sched_switch/trigger > > # cat events/sched/sched_switch/trigger > > # Available triggers: > > # traceon traceoff snapshot stacktrace enable_event disable_event > > enable_hist disable_hist hist > > ====== > > > > OK, it is cleared now. > > > > Now I test it again. > > > > ====== > > # echo 'hist:keys=pid:ts0=common_timestamp.usecs if comm=="cyclictest"' >> > > events/sched/sched_wakeup/trigger > > sh: write error: Invalid argument > > ====== > > > > Oops, what's the error? > > > > ====== > > # cat events/sched/sched_switch/hist > > > > ERROR: Variable already defined: ts0 > > Last command: keys=pid:ts0=common_timestamp.usecs if comm=="cyclictest" > > ====== > > > > Hmm, but ts0 is defined on sched_wakeup - you removed the triggers on > sched_switch, but I didn't see where you removed the sched_wakeup > trigger defining ts0... Ah, I confused that the sched_switch and sched_wakeup... Can you print out the error with which event we should see? e.g. ERROR: Variable already defined at sched_wakeup: ts0 And this shows the good reason why we should reject removing unexist trigger (with -ENOENT). If I find I can not remove 'hist:keys=pid:ts0=...' from sched_switch, it helps me to notice my mistake. > > Hmm, how can I undef ts0 and test it again? > > You should be able to remove the sched_wakeup trigger defining ts0 and > after doing that test again. At least I was able to: > > # echo '!hist:keys=pid:ts0=common_timestamp.usecs if comm=="cyclictest"' >> > events/sched/sched_wakeup/trigger > > # echo 'hist:keys=pid:ts0=common_timestamp.usecs if comm=="cyclictest"' > >> events/sched/sched_wakeup/trigger OK, anyway this works good to me too. Tested-by: Masami Hiramatsu <mhira...@kernel.org> Thanks, -- Masami Hiramatsu <mhira...@kernel.org>
