[gmx-developers] discussion of deprecation announcements in GROMACS 2021
David van der Spoel
spoel at xray.bmc.uu.se
Thu Dec 10 11:46:59 CET 2020
On 2020-12-10 09:54, Mark Abraham wrote:
> The developers announce functionality as deprecated each year. That
> gives users a chance to learn what changes may happen in future, so they
> can plan how to adapt.
> I've proposed several things to deprecate at
> <https://gitlab.com/gromacs/gromacs/-/issues/3818> and want to encourage
> people to consider those choices before I make an MR for the GROMACS
> 2021 release notes.
> Often things we announce as deprecated remain that way for months or
> years before we actually remove it. That's fine.
> The potentially controversial item is the proposed deprecation of OpenCL
> support. We have active funded projects to implement support with SYCL
> for Intel GPUs, and some as-yet undecided framework for AMD GPUs. When
> those are in place, the usefulness of OpenCL as a portable approach for
> GPU support in GROMACS has expired. We have not had the resources to
> develop the current CUDA and OpenCL GPU code forks to the same extent,
> and we are not going to be able to do that any better when SYCL and
> perhaps HIP are also around. Continuing to support and test the OpenCL
> functionality is work that we would need to do that costs us the
> opportunity to further improve the ports we expect users to be using in
> GROMACS 2022.
> So, when we have made enough progress on the Intel and AMD fronts, we
> want the freedom to remove the OpenCL port, so that there's less work
> for us to do and more freedom to adapt our GPU portability layer in the
> directions it needs to move. I hope that will happen some time during
> the 2021 calendar year, but it won't be January :-).
> Please feel free to discuss OpenCL here, and anything else at that
> gitlab issue!
The state of things with programming frameworks is rather miserable to
say the least. From the link below I read that HipSycl may cover both
AMD and Nvidia GPUs. However, looking a bit closer, only the expensive
AMD cards seem to be supported. We've been playing a bit with OpenMM
recently that has extensive OpenCL support, and even on old laptops
(Apple) that is a substantial improvement over using CPUs.
I guess there is no plan to abandon all the Nividia code in GROMACS for
something else, right?
David van der Spoel, Ph.D.,
Professor of Computational Molecular Biophysics
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