| 1 |
On Monday 18 December 2006 19:06, Mark Haney wrote: |
| 2 |
|
| 3 |
> I've been using -mcpu since I started using gentoo, but have been |
| 4 |
> noticing the '-mcpu is deprecated etc.' messages when updating. Being |
| 5 |
> the paranoid I am, I'd like to get rid of those, but haven't found the |
| 6 |
> correct option to use for -march. Is it the same as -mcpu? Or what's |
| 7 |
> the correct one for amd64? |
| 8 |
|
| 9 |
You can use -mtune in place of -mcpu. If you don't need binary |
| 10 |
compatibility with other CPUs, you should use -march. Speaking of |
| 11 |
which...that really depends. "amd64" means a lot of CPUs, including AMD |
| 12 |
and Intel models. What's your CPU? |
| 13 |
|
| 14 |
According to [1], you should set -march=k8 for AMD CPUs (non-EM64T) |
| 15 |
and -march=nocona for Intel ones (EM64T). But, for AMD athlon64 X2, you |
| 16 |
can also use -march=athlon64. [2] is a good reference, IMHO. |
| 17 |
|
| 18 |
If you want to optimize further, the forums have lots of threads devoted |
| 19 |
to CFLAGS optimization. |
| 20 |
|
| 21 |
[1] http://www.gentoo.org/doc/en/gentoo-amd64-faq.xml#cflags |
| 22 |
[2] http://gentoo-wiki.com/Safe_Cflags |
| 23 |
-- |
| 24 |
gentoo-amd64@g.o mailing list |
Archives