Hello Peter, 2012/7/10 Peter Zijlstra <pet...@infradead.org>: > On Wed, 2012-07-04 at 13:08 +0400, Andrew Vagin wrote: >> From: Peter Zijlstra <a.p.zijls...@chello.nl> >> >> A few events are interesting not only for a current task. >> For example, sched_stat_* are interesting to a task, which >> wake up. For this reason, it will be good, if such events will >> be delivered to a target task too. >> >> Now a target task can be set by using __perf_task(). > > Right, I suspect you actually tested this and it works?
Yes, of course I did. > > It would be good it you can expand the Changelog a bit to include your > entire use-case. Ok, I'm going to send a new version of this patch with your comments. > IIRC you're wanting to measure task block latency and > need the time and place where it goes to sleep, provided by > trace_sched_switch + callchain, and the time when it gets woken up, > provided by trace_sched_wakeup(). Actually sched_stat_* contains a time period for which a task slept. Now for profiling sleep times we need to do following actions: * Collect sched_switch and sched_stat_sleep events # ./perf record -e sched:sched_stat_sleep -e sched:sched_switch -gP -o perf.data.raw ~/foo * We need to combine sched_switch and sched_stat_sleep events. sched_switch contains a callchain and sched_stat_sleep contains a time period. I taught perf-inject to do that. It sets a period from sched_stat_sleep to a proper sched_switch. # ./perf inject -v -s -i perf.data.raw -o ./perf.data > > Hmm.. you only add __perf_task() to sched_stat_template, should it also > be added to sched_wakeup_template? Yes, it can be added. It may be useful for someone else. > > ISTR us talking about dis-allowing callgraphs on such cross-task events, > since that would be nigh impossible to interpret, right? > > So do we want something like this on top? Yes, you are right and I checked your code, it works fine. Thanks a lot for comments. If someone wants to try out my patches, he can clone the branch "prof-D-state" from it git://github.com/avagin/perf.git -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/