Le 22/09/2015 12:09, scott a écrit :
>> Interesting. Perhaps you have a newer version of Process Explorer? Or
>> maybe there's some setting somewhere to configure this that I haven't
>> noticed...
>
> v16.05 here, can't see any relevant setting.
>
> If I tell POV to render with 6 threads I only get 50% usage, but with 12
> threads I get 100% usage.
>
> However the elapsed times for the benchmark are:
> 6 threads  : 192s
> 12 threads : 136s
>
> So 50% CPU is actually more like 70% CPU, but I guess it depends on the
> exact algorithm (how nicely it can hyperthread).
>
 From my personal bench with povray, a HT-core is worth between 20 to 
25% of a real core. (tests done on i7 980X, at nominal speed, with 
benchmark scene)

If the OS is not total crap, the threads are allocated first on distinct 
real cores.

beware, when comparing with time, the performance is 1/time.

your 6 threads has a performance index of 5.20833, about 0.868 per thread
your 12 threads has one of 7.35, about .613 per threads.
(and if you remove the 5.208 from the 7.35, the additional HT-core only 
provides 2.142, that's 0.357 per HT-core, so a HT-core thread is in your 
system about 41% of a real core thread, for povray-binary and your scene).

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