Re: [PATCH 02/11] perf: Do not get values from disabled counters ingroup format read

[Peter Zijlstra]

On Wed, 2012-10-24 at 14:14 +0200, Jiri Olsa wrote:
> 
> well, x86_pmu_read calls x86_perf_event_update, which expects the
> event
> is active.. if it's not it'll update the count from whatever left in
> event.hw.idx counter.. could be uninitialized or used by others..
> 
Oh right, we shouldn't call ->read() unless ->state ==
PERF_EVENT_STATE_ACTIVE. Aside from that, perf_event_count() should
return the 'right' value regardless state (although excluding ERROR
might make sense).
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