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

[Smith, Barry F.]

  Mark,

   Would you be able to make one run using single precision? Just single everywhere since that is all we support currently? 

   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>