[petsc-users] Using PETSc GPU backend

[Ng, Cho-Kuen via petsc-users]

I installed PETSc on Perlmutter using "spack install petsc+cuda+zoltan" and 
used it by "spack load petsc/fwge6pf". Then I compiled the application code 
(purely CPU code) linking to the petsc package, hoping that I can get 
performance improvement using the petsc GPU backend. However, the timing was 
the same using the same number of MPI tasks with and without GPU accelerators. 
Have I missed something in the process, for example, setting up PETSc options 
at runtime to use the GPU backend?

Thanks,
Cho