[petsc-dev] Using PETSC with GPUs

[Barry Smith]

  Start by running a good size problem with -log_view (one MPI rank is best for all initial studies) and see the performance and the parts on the GPU. For a GPU your minimum problem size should be about 1 million unknowns!

  Feel free to send the -log_view output.

  Barry



> On Jan 14, 2022, at 4:27 PM, Rohan Yadav <rohany at alumni.cmu.edu> wrote:
> 
> Hi,
> 
> I'm looking to use PETSc with GPUs to do some linear algebra operations, like SpMV, SPMM etc. Building PETSc with `--with-cuda=1` and running with `-mat_type aijcusparse -vec_type cuda` gives me a large slowdown from the same code running on the CPU. This is not entirely unexpected, as things like data transfer costs across the PCIE might erroneously be included in my timing. Are there some examples of benchmarking GPU computations with PETSc, or just the proper way to write code in PETSc that will work for CPUs and GPUs?
> 
> Rohan