Re: Altivec in baseline for ppc64?
On 7/15/21 2:04 PM, Sébastien Villemot wrote:
>> Please go ahead and enabled AltiVec as I don't think it makes much sense to use BLAS
>> on machines without any SIMD support. If any user complains about compatibility issues,
>> please feel free to bring up the issue here again.
>
> I think I disagree with this idea. OpenBLAS can be pulled in by chains
> of dependencies, even for users who do not even know what BLAS is.
> Violating the baseline can lead to hard-to-understand crashes.
True, but all build servers we have support Altivec.
> Since I think that reliability is more important than performance, I
> prefer to strictly respect the baseline in the binary package.
Sure. But we could also just have observed whether any people report crashes.
> However note that locally recompiling OpenBLAS is a supported and
> documented procedure, for those who want to take full advantage of
> their hardware.
>
> Regarding the kernel that is currently built in the official binary, I
> could do with some help to determine which one is the best. You can see
> the list of kernels at this address:
> https://salsa.debian.org/science-team/openblas/-/tree/master/kernel/power
> Each KERNEL.* file lists a bunch of source files, many of which are
> assembly files.
> Currently, I use POWER4 for ppc64 and PPCG4 for powerpc, but I’m unsure
> that those are the right choice. I want a kernel that respects the
> baseline, but still taking advantage of all that is in the baseline.
I would have to look into that with more detail. We can probably also
discuss this on the #debian-ports IRC channel.
Adrian
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer - glaubitz@debian.org
`. `' Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
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