This might be interesting, but a bit vague. To be actionable I will need a little more information ....

Can you name the specific package, version, file, and function?

Does this function have a unit test (make check) and a repeatable performance test build into the package?

Otherwise this could turn into a bit of snip hunt.

On Wed, Oct 30, 2019 at 9:34 AM Dave Love <loveshack@fedoraproject.org> wrote:
[Posting, as this may be of general interest.]

Steven Munroe <munroesj52@gmail.com> writes:

> Now that pveclib <https://munroesj52.github.io/> is safely integrated as a
> Fedora package and Fedora 31 is released, I though it was time to offer my
> expertise to package developers doing vector code.

Thanks.  One possibility is the BLIS linear algebra library.  It
provides a BLAS interface, with which I guess means something if you do
SIMD implementation.  It currently has sub-optimal support on ppc64le,
since it uses generic C, not tuned code.  (GCC does vectorize the C --
despite the continuing doubts of the developers! -- but I don't
currently have access to POWER9 for measurements to find out how it
actually performs.)  IBM were supposed to be contributing a tuned
implementation, but that hasn't appeared, so I assume one would be
welcome.  There's a single micro-kernel to implement at a minimum,
though it might need separate ones for POWER 8 and 9.

The project home is https://github.com/flame/blis.  Un-merged code to
dispatch dynamically on POWER micro-architecture is under
https://github.com/flame/blis/pull/345 but isn't necessary.

[Reasons to prefer BLIS over OpenBLAS generally are support for AVX512
on x86_64 and potentially better threaded performance
<https://github.com/flame/blis/blob/master/docs/Performance.md>.
However, lack of dynamic micro-architecture selection for POWER and ARM
in the current release is a drawback, and OpenBLAS has more hand-tuning
of various operations that probably help some applications.]