[bug#29810] gnu: maths: Fix cache size detected by openblas on some

[ludo@gnu.org (Ludovic Courtès)]

Hi Dave,

Dave Love <fx@gnu.org> skribis:

> This addresses a potential performance problem, fixed in the post-0.2.20
> source.  It's intended for application to a package definition updated
> to 0.2.20, which Ludo said is in the pipeline.  Apologies that I don't
> seem to have converged on an acceptable style for changes.
>
>>From 23ad3a438ef7bcd34e2354f6cbdede634f0188d4 Mon Sep 17 00:00:00 2001
> From: Dave Love <fx@gnu.org>
> Date: Fri, 22 Dec 2017 12:48:29 +0000
> Subject: [PATCH 1/2] gnu: maths: Fix cache size detected by openblas on some
>  x86_64.
>
> * gnu/packages/patches/openblas-Add-dummy-implementation-of-cpuid_count-for-the-CPUI.patch,
> gnu/packages/patches/openblas-Use-cpuid-4-with-subleafs-to-query-L1-cache-size-on-.patch:
> New files.
> * gnu/packages/maths.scm (openblas)[source]: Use them.
> * gnu/local.mk: Register them.

Thanks for the patch.  Given the number of dependents, we would not push
it in master (info "(guix) Submitting Patches").  At the same time,
since 0.2.20 is in core-updates and well on its way, do you think we
should keep those patches?

Perhaps in core-updates we could keep both 0.2.19 with these patches and
0.2.20 (ISTR you said there were incompatibilities between these two
versions)?  Would it make sense?

Thanks,
Ludo’.