Re: [gentoo-user] Re: gentoo on the i7

On Sun, Apr 11, 2010 at 03:20:50AM +0100, Kerin Millar wrote:
> On 10/04/2010 23:06, luis jure wrote:
> >
> > hello list,
> >
> > after many years without a hardware upgrade, i'll be receiving my new
> > computer next week: intel i7 920 cpu, 6 GB ram, asus p6t mobo.
> >
> > i'm pretty excited, i imagine that at first i'll be shocked at the
> > difference with the ancient machine i'm using now.
> >
> > now my question: searching a bit for the best compilation flags for
> > this processor, i found this at gentoo-wiki:
> >
> > CHOST="x86_64-pc-linux-gnu"
> > CFLAGS="-march=core2 -msse4 -mcx16 -msahf -O2 -pipe"
> > CXXFLAGS="${CFLAGS}"
> > (http://en.gentoo-wiki.com/wiki/Safe_Cflags/Intel)
> >
> > on the other hand, a thread at http://forums.gentoo.org says that the
> > wiki page is outdated, and that -march=native should do the job without
> > any further tweaks like -msse4 etc.
>
> That is correct; -march=native will indeed do the job. The CFLAGS
> example you cite is clearly an interpretation of the flags that the
> native target would result in anyway.
>
> With respect to my Intel Xeon E3113, -march=native appears to equate to:
>
> -march=core2 -mtune=core2 -msahf -msse4.1 --param l1-cache-size=32
> --param l1-cache-line-size=64
>
> In short, use "native" and let the compiler take care of the details.
>
> Cheers,
>
> --Kerin
>
>

There's a thread in Installing Gentoo where a dev (can't remember which), that says native isn't the best option, but the best option indeed is to specify your arch. See these threads:
http://forums.gentoo.org/viewtopic-t-821639.html
http://forums.gentoo.org/viewtopic-t-821370.html 

-- 
Zeerak Waseem