Messages in this thread | | | Date | Fri, 18 Feb 2011 11:47:55 -0700 | From | David Ahern <> | Subject | Re: [PATCH 3/3] perf events: add timehist option to record and report |
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On 02/18/11 11:41, Arnaldo Carvalho de Melo wrote: > Em Fri, Feb 18, 2011 at 06:59:30PM +0100, Frederic Weisbecker escreveu: >> sched:sched_wait_task [Tracepoint event] >> sched:sched_wakeup [Tracepoint event] >> sched:sched_wakeup_new [Tracepoint event] >> sched:sched_switch [Tracepoint event] >> sched:sched_migrate_task [Tracepoint event] >> sched:sched_process_free [Tracepoint event] >> sched:sched_process_exit [Tracepoint event] >> >> >> You have the sched:sched_switch event and many others. >> >> Just try: >> >> perf record -a -e sched:* >> perf script >> >> perf-4128 [000] 19242.870025: sched_stat_runtime: comm=perf pid=4128 runtime=7430405 [ns] vruntime=3530192223488 >> perf-4128 [000] 19242.870042: sched_stat_runtime: comm=perf pid=4128 runtime=23142 [ns] vruntime=3530192246630 [n >> perf-4128 [000] 19242.870045: sched_stat_sleep: comm=kondemand/0 pid=59 delay=9979163 [ns] >> perf-4128 [000] 19242.870048: sched_wakeup: comm=kondemand/0 pid=59 prio=120 success=1 target_cpu=000 >> perf-4128 [000] 19242.870063: sched_stat_runtime: comm=perf pid=4128 runtime=21581 [ns] vruntime=3530192268211 [n >> perf-4128 [000] 19242.870066: sched_stat_wait: comm=kondemand/0 pid=59 delay=21581 [ns] >> perf-4128 [000] 19242.870069: sched_switch: prev_comm=perf prev_pid=4128 prev_prio=120 prev_state=R ==> next_comm >> kondemand/0-59 [000] 19242.870091: sched_stat_runtime: comm=kondemand/0 pid=59 runtime=27362 [ns] vruntime=35301862739 >> kondemand/0-59 [000] 19242.870094: sched_stat_wait: comm=perf pid=4128 delay=27362 [ns] >> kondemand/0-59 [000] 19242.870095: sched_switch: prev_comm=kondemand/0 prev_pid=59 prev_prio=120 prev_state=S ==> next >> >> And you can run your own script on these events: >> >> $ sudo ./perf script -g python >> generated Python script: perf-script.py >> >> Edit perf-script.py and then run it: >> >> $ perf script -s ./perf-script.py >> >> That also works for perl. >> >> The timestamps will be the cpu time and not the walltime, but at least that seems >> to be partly what you seek? > > The whole issue for him, AFAIK, is to correlate perf events with app > events. > > Think about tcpdump + networking tracepoints or 'perf probe' dynamic > events in the network stack, he wants to merge those logs and correlate > the tcpdump packet exchange with the tracepoints events in the network > stack, etc. > > I.e. it doesn't matter if it is ftrace or not, having a common clock > shared between apps and kernel tracing/whatever infrastructure is what > David is after, right?
A means of correlating the two, yes.
> > He can change userspace to use the clock the kernel is using in the > perf/ftrace/whatever infrastructure or make the kernel use the clock > userspace uses. > > The issue here is who will bend, u or k ;-)
It makes sense for ftrace, perf, etc to use a monotonic clock. That timestamp is nonsense to users (just a string of numbers) and application writers like those pretty little strings that relate to time has humans acknowledge it.
David
> > - Arnaldo
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