Messages in this thread | | | Date | Thu, 27 Nov 2014 11:56:03 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] perf tools: Do not fail on processing out of order event |
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* Arnaldo Carvalho de Melo <acme@redhat.com> wrote:
> Em Wed, Nov 26, 2014 at 04:39:31PM +0100, Jiri Olsa escreveu: > > Linus reported perf report command being interrupted due to > > processing of 'out of order' event, with following error: > > > > Timestamp below last timeslice flush > > 0x5733a8 [0x28]: failed to process type: 3 > > > > I could reproduce the issue and in my case it was caused by one > > CPU (mmap) being behind during record and userspace mmap reader > > seeing the data after other CPUs data were already stored. > > > > It'd be nice to find the source of this hiccup, meanwhile I'm > > submitting change that does not kill the processing, but only > > tracks the number of out of order events and warn user. > > Works, for me, thanks for the fast response!
Thanks Jiri!
> > --- a/tools/perf/util/session.c > > +++ b/tools/perf/util/session.c > > @@ -533,15 +533,11 @@ int perf_session_queue_event(struct perf_session *s, union perf_event *event, > > return -ETIME; > > > > if (timestamp < oe->last_flush) { > > - WARN_ONCE(1, "Timestamp below last timeslice flush\n"); > > - > > - pr_oe_time(timestamp, "out of order event"); > > + pr_oe_time(timestamp, "out of order event\n"); > > pr_oe_time(oe->last_flush, "last flush, last_flush_type %d\n", > > oe->last_flush_type); > > > > - /* We could get out of order messages after forced flush. */ > > - if (oe->last_flush_type != OE_FLUSH__HALF) > > - return -EINVAL; > > + s->stats.nr_unordered_events++;
Btw., in the forced flush case we'll get out of order events that are 'expected'. Shouldn't we count them separately and not warn about them, or so?
> > + if (session->stats.nr_unordered_events != 0) { > > + ui__warning("%u out of order events recorded.\n", > > + session->stats.nr_unordered_events); > > + }
Nit: I'd suggest keeping the message printout on a single line:
if (session->stats.nr_unordered_events != 0) { ui__warning("%u out of order events recorded.\n", session->stats.nr_unordered_events);
as IMHO the cure for this col80 linebreak checkpatch warning is worse than the disease! :-)
Barring those details:
Acked-by: Ingo Molnar <mingo@kernel.org>
Arnaldo, I suppose the fix will go upstream via your tree, as a pull request for v3.18 fixes?
Thanks,
Ingo
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