Frantisek Kluknavsky wrote:
Atlas aims for a relatively narrow set of use cases. No
virtualization.
No migration. Just the best possible performance on one given machine.
Virtual machines are notoriously known for varying performance. One can
not tune without exact benchmarking.
Of course, this means that it is a very poor choice for our de-facto default
LAPACK/BLAS. (Only the reference implementation is worse. Yet, we build some
stuff even against that!)
I'd suggest filing a Change to make OpenBLAS the default for F21 (when
hopefully the armv7 port will also be usable, so all our primary
architectures, even the silly one, will be covered) and working on building
everything in the distribution that uses LAPACK and/or BLAS against it.
Even if we keep the other BLAS/LAPACK implementations around, the target
should be that everything in the distro uses OpenBLAS, similarly to how we
made spellchecking use Hunspell throughout the distro (see
https://fedoraproject.org/wiki/Releases/FeatureDictionary). (I take it that
in this case, the application code should normally not need adjustments, so
this should be even easier than FeatureDictionary, and not end in a fiasco
such as the failed attempt at standardizing cryptography on NSS.)
Kevin Kofler