[Nix-dev] CPU optimized packages

[Shea Levy]

Hi Danny,

Unfortunately, there's not a good answer to this because -march=native 
is inherently impure. Is there any reason you can't tell users "Find out 
what -march=native means on your system and then fill in 
nixpkgs.config.extra_cflags with the result?" or some such (Note that 
config.extra_cflags doesn't currently exist AFAIK, but could)?

~Shea

On 02/07/2013 07:36 AM, Danny Wilson wrote:
> With help of the gentoo wiki ( 
> http://en.gentoo-wiki.com/wiki/Hardware_CFLAGS )
> I found this produces a nice GCC option list:
>
> echo "" | gcc -O3 -march=native -mtune=native -v -E - 2>&1 |grep cc1 
> |sed -r 's/.*? - -(.*)$/-\1/'
>
>
>
>> Danny Wilson <mailto:danny at prime.vc>
>> 7 februari 2013 12:37
>> I'd like some packages to be optimized for my server CPU. GCC has
>> -march=native for this, but that would not generate a cpu specific nixos
>> hash.
>>
>> Is there a nix expression available which adds something like this:
>> gcc -march=native -Q --help=target |grep enabled
>>
>> to CFLAGS and correctly hashing it?
>>
>>
>>
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