[petsc-dev] Kokkos/Crusher perforance

[Jed Brown]

Barry Smith <bsmith at petsc.dev> writes:

>> What is the command line option to turn PetscLogGpuTimeBegin/PetscLogGpuTimeEnd into a no-op even when -log_view is on? I know it'll mess up attribution, but it'll still tell us how long the solve took.
>
>   We don't have an API for this yet. It is slightly tricky because turning it off will also break the regular -log_view for some stuff like VecAXPY(); anything that doesn't have a needed synchronization with the CPU.) 

Of course it will misattribute time, but the high-level (like KSPSolve) is still useful. We need an option for this so we can still have -log_view output.

Note that Mark's logs have been switching back and forth between -use_gpu_aware_mpi and changing number of ranks -- we won't have that information if we do manual timing hacks. This is going to be a routine thing we'll need on the mailing list and we need the provenance to go with it.