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Re: fftw runtime cpu detection
From: |
Ludovic Courtès |
Subject: |
Re: fftw runtime cpu detection |
Date: |
Fri, 06 Apr 2018 17:09:21 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) |
Eric Bavier <address@hidden> skribis:
> On Fri, Apr 06, 2018 at 10:05:43AM +0200, Ludovic Courtès wrote:
>> Hello Eric,
>>
>> Eric Bavier <address@hidden> skribis:
>>
>> > I recently discovered that the FFTW library can do runtime cpu
>> > detection. In order to do this, the package needs to be configured to
>> > build SIMD "codelets", like how our 'fftw-avx' currently does. Then,
>> > based on the instruction support detected at runtime, make those
>> > kernels available to the fftw "planner" for execution.
>>
>> That’s really good news! Thanks for testing it.
>>
>> The patch LGTM. Can you confirm that the planner won’t ever try to use
>> the AVX2 codelets, for instance when running the test suite on an x86_64
>> box that lacks AVX2?
>
> Yes, I've successfully run 'make check' on an sse2-only machine where
> '--enable-avx' and '--enable-avx2' where configured. I'll check on an
> i686 machine tonight.
OK.
>> If that’s the case, I’d be in favor of pushing this patch to core-updates.
>
> Great. I'll do some more testing. Should I send a finalized patch to
> guix-patches when it's ready?
If Marius has no objections, I think you could push it directly to
core-updates.
Thank you,
Ludo’.