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wiki page is outdated, and that -march=native should do the job without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