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 wiki page is outdated, and that -march=native should do the job without 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
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