[PATCH] perf/Power: PERF_EVENT_IOC_ENABLE does not reenable event
sukadev at linux.vnet.ibm.com
Fri Jan 25 10:29:07 EST 2013
Paul Mackerras [paulus at samba.org] wrote:
| > + /*
| > + * If this event was disabled in record_and_restart() because we
| > + * exceeded the ->event_limit, this is probably a good time to
| > + * re-enable the event ? If we don't reenable the event, we will
| > + * never notify the user again about this event.
| > + */
| The comment seems a bit tentative. :) If the PERF_EF_START bit is set
| then we are being told to restart the event.
| > if (!(ef_flags & PERF_EF_START))
| > event->hw.state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
| > + else
| > + event->hw.state &= ~PERF_HES_STOPPED;
| This looks fine, though I think you could equally well just set
| event->hw.state to 0 in the else clause. That would clear the
| UPTODATE flag too, which is appropriate since we are about to put the
| event on a hardware counter.
Agree. I submitted a new patch with better comments and patch description
and cleared the state to 0.
Thanks for the review.
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