[petsc-users] GPU speedup in Poisson solvers

[Chung Shen]

Dear PETSc Users,

I am new to PETSc and trying to determine if GPU speedup is possible with the 3D Poisson solvers. I configured 2 copies of 'petsc-master' on a standalone machine, one with CUDA toolkit 5.0 and one without (both without MPI):
Machine: HP Z820 Workstation, Redhat Enterprise Linux 5.0
CPU: (x2) 8-core Xeon E5-2650 2.0GHz, 128GB Memory
GPU: (x2) Tesla K20c (706MHz, 5.12GB Memory, Cuda Compatibility: 3.5, Driver: 313.09)

I used 'src/ksp/ksp/examples/tests/ex32.c' as a test and was getting about 20% speedup with GPU. Is this reasonable or did I miss something?

Attached is a comparison chart with two sample logs. The y-axis is the elapsed time in seconds and the x-axis corresponds to the size of the problem. In particular, I wonder if the numbers of calls to 'VecCUSPCopyTo' and 'VecCUSPCopyFrom' shown in the GPU log are excessive?

Thanks in advance for your reply.

Best Regards,

Chung Shen
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