Hi Jakob,
I'm going to try working on this this week. I'll let you know once
there is a PR.
Micael
On 1/12/19 8:17 AM, Jakob Schiøtz wrote:
Hi Michael,
That would indeed be great. Let us keep in touch, so we don’t do it both :-)
Jakob
On 11 Jan 2019, at 16:19, Micael Oliveira <micael.olive...@mpsd.mpg.de> wrote:
Hi,
I'm planning on writing a custom easyblock for ELPA precisely to tackle this
problem, so I guess I'm the person mentioned in Alan's email, although I'm
still not sure I can attend the EasyBuild user meeting.
My idea was precisely to use the FFTW easyblock as a starting point.
Best regards,
Micael
On 1/11/19 3:34 PM, Kenneth Hoste wrote:
Dear Jakob,
I'm not sure there's much EasyBuild can do about this, unless I'm missing
something.
You can build using different sets of configuration options in a single
installation, but I don't think that's of much use here.
The best solution indeed seems to be to write an easyblock for ELPA that checks
which CPU capabilities are supported, and then builds ELPA with the appropriate
configure options.
We have some of that already in custom easyblocks, see for example the FFTW
easyblock:
https://github.com/easybuilders/easybuild-easyblocks/blob/master/easybuild/easyblocks/f/fftw.py#L124
.
This really is beyond what's possible in an easyconfig file, you need custom
code to deal with this...
regards,
Kenneth
On 11/01/2019 12:48, Jakob Schiøtz wrote:
Dear all,
I did not get any response to this before Christmas. Does anybody have any
ideas that might help me?
Best regards
Jakob
On 18 Dec 2018, at 15:00, Jakob Schiøtz <schi...@fysik.dtu.dk> wrote:
Hi,
I am trying to build the newest version of ELPA (Eigenvalue SoLvers for
Petaflop-Applications, https://elpa.mpcdf.mpg.de/). It looks like ELPA builds
a number of “kernels” that are chosen at runtime depending on the capabilities
of the CPU, for example SSE, AVX, AVX2 or AVX512.
Unfortunately, with the foss toolchain the compiler refuses to build these
kernels if the CPU does not support them (the Intel toolchain happily builds
them). This means that I have to configure ELPA with --disable-avx2 or
--disable-avx if the CPU does not support these instructions, and
--enable-avx512 if the CPU does support that.
Is there some way to do this easily in an easyconfig? Maybe a compiler flag
that allows using “AVX2 gcc intrinsics” in the code, without otherwise turning
on AVX2 instructions (as that would cause the rest of the code to fail if AVX2
is not supported).
Or do I have to write some complicated stuff into an easyblock? And if I do
the latter, do you know how to portably detect the capabilities of the CPU?
It seems somewhat silly that the ELPA configure script tests if these
instructions are supported and fails if one does not manually disable the
unsupported versions instead of just doing the right thing. But that is beyond
my control.
Best regards
Jakob
--
Jakob Schiøtz, professor, Ph.D.
Department of Physics
Technical University of Denmark
DK-2800 Kongens Lyngby, Denmark
http://www.fysik.dtu.dk/~schiotz/
--
Jakob Schiøtz, professor, Ph.D.
Department of Physics
Technical University of Denmark
DK-2800 Kongens Lyngby, Denmark
http://www.fysik.dtu.dk/~schiotz/
--
Jakob Schiøtz, professor, Ph.D.
Department of Physics
Technical University of Denmark
DK-2800 Kongens Lyngby, Denmark
http://www.fysik.dtu.dk/~schiotz/
