* Arnaldo Carvalho de Melo <[email protected]> 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 <[email protected]>
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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