[gmx-developers] Branches w/working OpenCL support

[Mark Abraham]

Hi Mirco,

Thanks very much for the help testing!

On Sun, Jun 7, 2015 at 12:23 PM Mirco Wahab <
mirco.wahab at chemie.tu-freiberg.de> wrote:

> Hi Szilard,
>
> On 31.05.2015 22:15, Szilárd Páll wrote:
> > [...]
> > https://gerrit.gromacs.org/#/c/4314/
> > Use the version in review on gerrit I linked above, that's the most up
> > to date code.
> >[...]
>
> I completed some tests using an AMD device (Pitcairn-GPU,
> Radeon R9-270X), and used adh_cubic_vsites, rnase_cubic, and
> villin_vsites from the "gromacs acceleration page".
>
> So far, the simulations appear to run stable and deliver correct
> results if *no pressure coupling* is used. As I noted already with
> the NV opencl test, this affects the AMD opencl implementation too:
> pressure coupling just don't work so far.
>

I believe the same GPU auto-tuning bug that was fixed for 5.0.2 may be to
blame here. (The OpenCL branch fork preceded this fix.) I have uploaded a
possible fix in patch set 21 at the above link. I'll plan to test it
~Wednesday, but don't have time now.

Compilation: there needs to be an additional include of
> #include <algorithm> in src/gromacs/gmxana/gmx_wham.cpp
> in order to provide std::min/max for VC. Another problem
> is the use of binary numerals in src\gromacs\listed-forces\bonded.cpp,
> which are C++14. Maybe these could be written in hexadecimal
> numerals in order to avoid problems w/non C++14-compilers?
>
> Pressure coupling: Depending on the simulation setup w/pressure
> coupling, gmx will  either crash immediately (when using pme) or
> continuously enlarge the volume (eg. when using rf + berendsen).
>

Hmm, not sure any more if RF can trigger the issue I've fixed above, but
testing will show!

Mark


>
> I put the log files an a host, these include log files and
> input for a very simple spc water system w/pressure coupling
> (which doesn't work w/opencl but works perfectly using -nb cpu).
>
> http://spule.compch.tu-freiberg.de/~wahab/gromacs/gmx_opencl_2015-06_szilard.zip
>
> short overview:
>
>   adh_cubic_vsites
>    cpu/pme:     5.738,  gpu/pme:        17.421
>    cpu/rf:      7.913,  gpu/rf:         26.344
>
>   rnase_cubic
>    cpu/pme:     15.001, gpu/pme:        39.363
>    cpu/rf:      24.729, gpu/rf:         59.179
>
>   villin_vsites
>    cpu/pme:     124.86, gpu/pme:        284.213
>    cpu/rf:      151.05, gpu/rf:         310.794
>
>   (water_small_npt/nvt)
>    cpu/pme/npt: 20.00   gpu/pme/npt:    n/a
>    cpu/pme/nvt: 21.65   gpu/pme/nvt:    52.05
>
>
> How is the current status for the planned inclusion of
> opencl into a gromacs release?
>
> Regards,
>
> M.
>
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