Source: openblas
Version: 0.2.20+ds-1
Severity: wishlist
From Changelog.txt in OpenBLAS 0.2.20:
IBM Z: * New target z13 with BLAS3 optimizations
I have just checked, and openblas/0.2.20-3 builds successfully on zelenka.debian.org.
Please enable building on s390x.
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 [1]).
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 [1]).
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.
the question will be then : does the buildd support these instructions ?
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 [1]).
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.
On 09/14/2017 09:58 AM, Sébastien Villemot wrote:
On Wed, Sep 13, 2017 at 08:33:08PM +0000, PICCA Frederic-Emmanuel wrote:
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 [1]).
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.
On Thu, Sep 14, 2017 at 12:34:34PM +0200, Christian Borntraeger wrote:
On 09/14/2017 09:58 AM, Sébastien Villemot wrote:
On Wed, Sep 13, 2017 at 08:33:08PM +0000, PICCA Frederic-Emmanuel wrote:
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 [1]).
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.
Thanks for your feedback. I have opened a request upstream about the need for a
z900 kernel, and for a dynamic selection between the z900 and z13 kernels
(as OpenBLAS currently does on x86).
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