Re: [gentoo-user] cpu flags / USE flags / compiler flags

[Mark Knecht <markknecht@gmail.com>]

I agree with Ellotheth that it seems like there's an opportunity to
come up with a good optimization doc but the paper is interesting. The
answers might not be the same for P4 vs. AMD vs. sparc vs. Apple.
Maybe a suite of files that get compiled, generate the numbers and
instruct you what might work best?

Interesting info. thanks.

- Mark

On 9/3/05, Volker Armin Hemmann <volker.armin.hemmann@tu-clausthal.de> wrote:
> On Sunday 04 September 2005 05:27, waltdnes@waltdnes.org wrote:
> 
> >
> >   That list shows pentium4, mmx, sse, and sse2.  Also, if you have *ANY*
> > version of sse available, you can improve performance by running floating
> > point math via sse, rather than 387 instructions.  I recommend...
> >
> > CFLAGS="-O2 -pipe -fomit-frame-pointer -march=pentium4 -mmmx -msse -msse2
> > -mfpmath=sse"
> >
> >
> 
> emm. I would not do this.
> 
> 
> -mfpmath=sse seems to be slower than -fpmath=387
> 
> http://www.anandtech.com/mac/showdoc.aspx?i=2436&p=5
> 
> has the numbers/made the experience.
> 
> It seems, that gcc is not he best optimizer in the world ;)
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> gentoo-user@gentoo.org mailing list
> 
>

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