On 12/06/15 15:36, Arnaldo Carvalho de Melo wrote: > Em Fri, Jun 12, 2015 at 02:09:38PM +0200, Peter Zijlstra escreveu: >> On Fri, Jun 12, 2015 at 02:12:11PM +0300, Adrian Hunter wrote: >>> On 11/06/15 17:15, Peter Zijlstra wrote: >> >>>> Right, so the one wee problem I have is that this only provides sched_in >>>> data, I imagine people might be interested in sched_out as well. >>> >>> That is not a problem although it would be interesting to know the use-case. >>> To me it seemed unreasonable to expect to analyze scheduler behaviour >>> without admin-level privileges since it is inherently an administrative >>> activity. >> >> I was more thinking about it being used to track event duration inside a >> task. Say you want measure the time between event A and event B but got >> scheduled out in between. >> >> ---- A ----] .... [---- B ----- >> >> If you do not have the sched_out time, you cannot correct for that.
Thanks for the example. >> >>>> all 3 are already part of sample_id. >>> >>> You have to decide whether you expect to be able to use an event without >>> sample_id. MMAP and MMAP2 both have pid, tid which are in sample_id, LOST >>> has id, EXIT and FORK have time, all of the THROTTLE/UNTHROTTLE members are >>> in sample_id etc. So it currently looks like we expect to be able to use an >>> event without requiring sample_id. > > The fact that there is this duplication is because sample_id_all came > after those events, but this new one being proposed doesn't have to do > it :-) Thanks, that's clear then. There will just need to be a flag to indicate whether it is scheduling in or out. > >> I think we recently had this discussion: >> >> lkml.kernel.org/r/[email protected] >> >> The patch we ended up merging: >> >> f38b0dbb491a ("perf/x86/intel: Introduce PERF_RECORD_LOST_SAMPLES") >> >> Does indeed require sample_id. > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
