Re: Optionally using more advanced CPU features

[Ben Woodcroft <b.woodcroft@uq.edu.au>]

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Hi,


On 21/08/17 22:23, Ricardo Wurmus wrote:
> Hi Guix,
>
> I was wondering how we should go about optionally building software for
> more advanced CPU features.  Currently, we build software for the lowest
> common feature set among x86_64 CPUs.  That’s good for portability, but
> not so good for performance.
In many cases we can set the --with-arch flag when configuring GCC, so 
that packages built with that GCC are optimised for that architecture by 
default.

We have discussed this in the past, 
(https://lists.gnu.org/archive/html/guix-devel/2016-10/msg00005.html) 
but as you say individual packages sometimes need individual attention.

Anyway, to move forward I created a repo so that package recipes can be 
modified to use a GCC that has been optimised for a particular 
architecture. I put it out there so that it is more than just a patch on 
this ML, but I'd be happy to incorporate it into Guix proper if that is 
desired.
https://github.com/wwood/cpu-specific-guix

For instance, to build DIAMOND optimised for sandybridge:

GUILE_LOAD_PATH=/path/to/cpu-specific-guix:$GUILE_LOAD_PATH\ |guix build -e '(begin (use-modules (cpu-specific-guix) (gnu packages 
bioinformatics))\ (cpu-specific-package diamond "sandybridge"))'|



HTH, ben

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