Bug#919272: Is multiple-layers of alternatives a good thing to users?

[Mo Zhou]

Hi Guus,

On Mon, Feb 04, 2019 at 07:55:41AM +0100, Guus Sliepen wrote:
> >  libblis.so.2 libblis2 #MINVER#
> 
> If the ABI and API are the same for all variants, a much better
> solutions seems to me to have a single libblis2 that can switch at
> runtime between the different variants, perhaps using an environment
> variable to decide. That would require some support from upstream
> though.

Yes, I agree that such support is better. Actually the libmkl-rt library
from intel-mkl (non-free) supports the feature you said[1], and its
quite convenient. However for the BLIS upstream I think they don't have
enough fund and energy to develop such a feature. Based on that,
the current solution looks good enough.

[1] Env var MKL_THREADING_LAYER={intel,gnu,tbb,sequential}
    allows to to switch threading model among libiomp5, libgomp,
	libtbb2, and none.