Messages in this thread | | | Date | Wed, 11 May 2016 11:13:33 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 2/2] perf: Disable the event on a truncated AUX record |
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On Tue, May 10, 2016 at 04:18:33PM +0300, Alexander Shishkin wrote: > When the PMU driver reports a truncated AUX record, it effectively means > that there is no more usable room in the event's AUX buffer (even though > there may still be some room, so that perf_aux_output_begin() doesn't take > action). At this point the consumer still has to be woken up and the event > has to be disabled, otherwise the event will just keep spinning between > perf_aux_output_begin() and perf_aux_output_end() until its context gets > unscheduled. > > Again, for cpu-wide events this means never, so once in this condition, > they will be forever losing data. > > Fix this by disabling the event and waking up the consumer in case of a > truncated AUX record.
> + if (wakeup) { > + if (truncated) > + handle->event->pending_disable = 1; > + perf_output_wakeup(handle); > + }
Does the userspace tool know how to deal with this and re-enable it?
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