Changing the default 32-bit x86 arch for Fedora 12 (#2)

[Steven Moix]

On 06/17/2009 07:52 PM, Bill Nottingham wrote:
> Given the loud feedback, I've updated the proposal at:
> 	https://fedoraproject.org/wiki/Features/F12X86Support
>
> The revised proposal:
>
> - Build all packages for i686 (this requires cmov)
> - Optimize for Atom
>
> Why?
>
> - We don't really support i586 in any meaningful matter
> - OLPC still works with base i686
> - We are likely doing a mass rebuild for F-12 anyways, might as well switch
>    while we're doing it
> - Atom is the only currently produced 32-bit x86 chip of note; optimize
>    for what's currently available
>
> If you want numbers, I did some benchmarking of code [1] with various
> build options on a variety of processors, with the F-11 gcc code. All
> of these results are relative to a F-11 baseline of "-march=i586
> -mtune=generic".
>
> 		P4 2.4Ghz	Athlon 3400+	Core2Duo E6850	Atom N270
> march=i686/	-1.1%		+2.0%		+0.9%		+0.6%
>   mtune=generic
> march=i586/	+0.3%		-0.3%		-0.2%		+1.3%
>   mtune=atom
> march=i686/	-1.5%		+1.2%		+0.5%		+1.7%
>   mtune=atom
>
> Bill
>
> [1] gzip, bzip2, math simulation, mp3 encode/decode, ogg encode/decode
>

This sounds a perfectly fine and sensible solution to me, thanks for 
taking the feedback into account :)

Steven