* Mike Galbraith <bitbuc...@online.de> wrote:
> On Tue, 2013-06-25 at 18:01 +0200, Mike Galbraith wrote:
> > On Thu, 2013-06-20 at 14:46 -0500, Dave Chiluk wrote:
> > > Running the below testcase shows each process consuming 41-43% of it's
> > > respective cpu while per core idle numbers show 63-65%, a disparity of
> > > roughly 4-8%. Is this a bug, known behaviour, or consequence of the
> > > process being io bound?
> >
> > All three I suppose.
>
> P.S.
>
> perf top --sort=comm -C 3 -d 5 -F 250 (my tick freq)
> 56.65% netserver
> 43.35% pert
>
> perf top --sort=comm -C 3 -d 5
> 67.16% netserver
> 32.84% pert
>
> If you sample a high freq signal (netperf TCP_RR) at low freq (tick),
> then try to reproduce the original signal, (very familiar) distortion
> results. Perf doesn't even care about softirq yada yada, so seems it's
> a pure sample rate thing.
Would be very nice to randomize the sampling rate, by randomizing the
intervals within a 1% range or so - perf tooling will probably recognize
the different weights.
Thanks,
Ingo
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