[Libav-user] gcc auto-vectorisation

"René J.V. Bertin" rjvbertin at gmail.com
Wed Feb 27 17:46:11 CET 2013

On Feb 27, 2013, at 17:37, Claudio Freire wrote:

>> Detailed benchmark results: (32 bit, MMX/SSE code, -fno-tree-vectorize)
>>                   samples          user t        kernel t          real t           CPU %
>> Video decode  :      85166         27.0846s        2.48361s        13.5333s        218.484%
> Wait... 200%... what's your hardware like?
> If by any chance you have Hyper Threading enabled (which is quite
> likely), then I bet that's what the penalty is coming from (there's

Ah, ok. I have a dual core, hyper-threaded i7 . Do you think there's an interest other than academic to deactivate hyper threading?


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