Re: kernel + gcc 4.1 = several problems

From: Linus Torvalds
Date: Wed Jan 03 2007 - 11:16:02 EST




On Wed, 3 Jan 2007, Alan wrote:
>
> > cmov is effectively the same cost as a compare and jump, in both cases
> > the cpu needs to do a prediction, and on a mispredict, restart.
>
> On a P4 it appears to be slower than compare/jump in most cases

On just about EVERYTHING it's slower than compare/jump. See my other post
on why, together with a (largely untested) test app.

Linus
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