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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.


>> 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

Thank you,

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