Re: [PATCH V8 7/8] perf, x86: introduce PERF_RECORD_LOST_SAMPLES

[Peter Zijlstra]

On Thu, May 07, 2015 at 01:56:09PM +0000, Liang, Kan wrote:
> 
> > 
> > 
> > So I changed it slightly to the below; changes are:
> > 
> >  - record 'lost' events to all set bits; after all we really do not
> >    know which event this sample belonged to, only logging to the first
> >    set bit seems 'wrong'.
> 
> If so, the same dropped sample will be count multiple times. It's hard to know
> the exact number of dropped samples.

OTOH if the events are from different consumers, they might think there
are no samples lost, while in fact there are.
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