On 09/14/2017 09:58 AM, Sébastien Villemot wrote: > On Wed, Sep 13, 2017 at 08:33:08PM +0000, PICCA Frederic-Emmanuel wrote: >> Hello >> >>> Unfortunately it does not look that simple. OpenBLAS is optimized for z13, >>> but >>> our s390x port is supposed to support all the z systems (see ). >> >> what about asking for a a z13-support package to the isa-support (source >> package) maintainer. This way it could be possible to upload an optimise >> vesion of openblas which can install on recent enought s390x machines. > > I am not totally convinced by this solution. If we adopt it, somebody who > installs e.g. octave on an old system-z machine will be hit by a failure in > the > dpkg installation process, which needs manual intervention. This is likely to > generate problems in automated installers (and also confuse and annoy system > admins). > >> the question will be then : does the buildd support these instructions ? > > I leave that to the s390 porters to answer.
FWIW, some years ago I did the atlas port for s390x. For dynamic linking the atlas build/package process did support the exploitation of ELF HW_CAPS. So you could build a z900 (generic) and a z13 variant which is then picked by the linker at runtime. No idea if openblas allows the same. Of course the static variant (.a) must be the generic one. Christian