[gmx-users] SSE4 → AVX2

[nicola staffolani]

Thanx Szilárd!

The concept of cross compilation is not perfectly 100% clear to me :s

software: GROMACS 4.6.5
hardware: Intel® Core™ i7-4790 CPU @ 3.60GHz × 8
message: Compiled acceleration: SSE4.1 (Gromacs could use AVX_256 on this
machine, which is better)

Have I given you the info you had requested?





2014-08-27 12:00 GMT+02:00 Szilárd Páll <pall.szilard at gmail.com>:

> Normally the highest supported SIMD instructions set, which is in your
> case AVX2, is detected during configuration phase. The fact that you
> are getting that message means that:
> - you are cross-compiling on an SSE4.1 node (e.g. cluster head node)
> for AVX2 machines;
> - your compiler does not support AVX/AVX2 and SSE4.1 was chosen as
> fallback; cmake should have warned about this during configuration.
>
> What is your hardware/software setup? Using -DGMX_SIMD=AVX2 should
> work in the former case.
>
> Cheers,
>
> --
> Szilárd
>
>
> On Wed, Aug 27, 2014 at 10:44 AM, nicola staffolani
> <n.staffolani at unitus.it> wrote:
> > Dear Gromacs users & developers,
> >
> > my computer tells me that, if I'd use AVX_256 instead of SSE4, then my
> > simulations would be done much faster. Which changes in which files do I
> > have to do in order to achieve this? I have serched the mailing list but
> > couldn't find the explicit answer: I warn you that I am not so much of a
> > geek, therefore suggesting me, for example, to change the path, without
> > telling me which precise actions I have to carry on (for example, as
> > already said, which lines I have to change/add in which file) in order to
> > achieve this, will only generate the next email from my side and then,
> > since by then you will have already started answering me, you will lose
> > more time answering me back than if you would have precisely described in
> > the first reply the order of precise actions needed to be done in order
> to
> > achieve the goal ;)
> >
> > Thank you for helping and have a nice day/night,
> >
> > Nicola
> > --
> > Nicola Staffolani PhD
> > Biophysics & Nanoscience Centre CNISM <http://www.unitus.it/biophysics>
> > Università della Tuscia
> > Largo dell'Università s.n.c., I-01100 Viterbo
> > email: n.staffolani at unitus.it
> > tel.: +39 0761 35 70 27; fax: +39 0761 35 71 36
> > --
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-- 
Nicola Staffolani PhD
Biophysics & Nanoscience Centre CNISM <http://www.unitus.it/biophysics>
Università della Tuscia
Largo dell'Università s.n.c., I-01100 Viterbo
email: n.staffolani at unitus.it
tel.: +39 0761 35 70 27; fax: +39 0761 35 71 36