[petsc-dev] [petsc-maint] running CUDA on SUMMIT

[Mark Adams]

On Wed, Aug 14, 2019 at 2:35 PM Smith, Barry F. <bsmith at mcs.anl.gov> wrote:

>
>   Mark,
>
>    Would you be able to make one run using single precision? Just single
> everywhere since that is all we support currently?
>
>
Experience in engineering at least is single does not work for FE
elasticity. I have tried it many years ago and have heard this from others.
This problem is pretty simple other than using Q2. I suppose I could try
it, but just be aware the FE people might say that single sucks.


>    The results will give us motivation (or anti-motivation) to have
> support for running KSP (or PC (or Mat)  in single precision while the
> simulation is double.
>
>    Thanks.
>
>      Barry
>
> For example if the GPU speed on KSP is a factor of 3 over the double on
> GPUs this is serious motivation.
>
>
> > On Aug 14, 2019, at 12:45 PM, Mark Adams <mfadams at lbl.gov> wrote:
> >
> > FYI, Here is some scaling data of GAMG on SUMMIT. Getting about 4x GPU
> speedup with 98K dof/proc (3D Q2 elasticity).
> >
> > This is weak scaling of a solve. There is growth in iteration count
> folded in here. I should put rtol in the title and/or run a fixed number of
> iterations and make it clear in the title.
> >
> > Comments welcome.
> >
> <out_cpu_012288><out_cpu_001536><out_cuda_012288><out_cpu_000024><out_cpu_000192><out_cuda_001536><out_cuda_000192><out_cuda_000024><weak_scaling_cpu.png><weak_scaling_cuda.png>
>
>
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