Re: [PATCH 15/34] perf, core: Add a concept of a weightened sample

[Andi Kleen]

On Tue, Oct 23, 2012 at 03:13:52PM +0200, Peter Zijlstra wrote:
> > @@ -562,6 +565,7 @@ enum perf_event_type {
> >          *      { u64                   stream_id;} && PERF_SAMPLE_STREAM_ID
> >          *      { u32                   cpu, res; } && PERF_SAMPLE_CPU
> >          *      { u64                   period;   } && PERF_SAMPLE_PERIOD
> > +        *      { u64                   weight;   } && PERF_SAMPLE_WEIGHT
> >          *
> >          *      { struct read_format    values;   } && PERF_SAMPLE_READ
> >          * 
> 
> So the only issues I have are that his makes every sample more expensive
> by having to 0 out that weight data and the sample placement.

It's only reported when explicitely enabled (-W). So most users
shouldn't see any overhead (except two untaken if()s or so)

-Andi

-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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