On Mon, May 1, 2023 at 8:14 AM Andrew Ho <helloworld...@gmail.com> wrote:
> Hi, > > I noticed that when I compile PETSc/HYPRE with GPU support, it demands > that I use GPU vectors/matrices (in the form of either > VECCUDA/MATMPIAIJCUSPARSE, VECHIP/MATMPIAIJHIPSPARSE, or > VECKOKKOS/MATMPIAIJKOKKOS). However, I would like to do some > comparisons/tuning vs. CPU solvers for my particular application, and when > I try to pass in regular CPU vectors/sparse matrices, PETSc complains: > > [0]PETSC ERROR: Invalid argument > [0]PETSC ERROR: HYPRE_MEMORY_DEVICE expects a device vector. You need to > enable PETSc device support, for example, in some cases, -vec_type cuda > [0]PETSC ERROR: See https://petsc.org/release/faq/ for trouble shooting. > [0]PETSC ERROR: Petsc Development GIT revision: v3.19.1-126-g02e62876438 > GIT Date: 2023-04-30 09:10:41 -0500 > [0]PETSC ERROR: ./myprog on a named butter by pb Sun Apr 30 23:07:05 2023 > [0]PETSC ERROR: Configure options --prefix=/home/pb/opt/petsc/3.19.1 > --with-debugging=0 --with-large-file-io=1 --with-hdf5-dir=/home/pb/.local > --download-hypre --download-metis --download-parmetis > --download-superlu_dist --COPTFLAGS=-O3 --FOPTFLAGS=-O3 --CXXOPTFLAGS=-O3 > --CUDAOPTFLAGS=-O3 --with-64-bit-indices=1 --download-slepc > --download-fblaslapack --with-cuda --with-kokkos-dir=/home/pb/.local > --with-kokkos-kernels-dir=/home/pb/.local --with-openmp > [0]PETSC ERROR: #1 VecGetArrayForHYPRE() at > /scratch/pb/code/third_party/petsc/petsc/src/vec/vec/impls/hypre/vhyp.c:95 > [0]PETSC ERROR: #2 VecHYPRE_IJVectorPushVecRead() at > /scratch/pb/code/third_party/petsc/petsc/src/vec/vec/impls/hypre/vhyp.c:138 > [0]PETSC ERROR: #3 PCApply_HYPRE() at > /scratch/pb/code/third_party/petsc/petsc/src/ksp/pc/impls/hypre/hypre.c:433 > [0]PETSC ERROR: #4 PCApply() at > /scratch/pb/code/third_party/petsc/petsc/src/ksp/pc/interface/precon.c:441 > > [0]PETSC ERROR: #5 KSP_PCApply() at > /scratch/pb/code/third_party/petsc/petsc/include/petsc/private/kspimpl.h:381 > [0]PETSC ERROR: #6 KSPInitialResidual() at > /scratch/pb/code/third_party/petsc/petsc/src/ksp/ksp/interface/itres.c:64 > [0]PETSC ERROR: #7 KSPSolve_GMRES() at > /scratch/pb/code/third_party/petsc/petsc/src/ksp/ksp/impls/gmres/gmres.c:226 > [0]PETSC ERROR: #8 KSPSolve_Private() at > /scratch/pb/code/third_party/petsc/petsc/src/ksp/ksp/interface/itfunc.c:898 > [0]PETSC ERROR: #9 KSPSolve() at > /scratch/pb/code/third_party/petsc/petsc/src/ksp/ksp/interface/itfunc.c:1070 > [0]PETSC ERROR: #10 main() at > /home/pb/code/misc/kokkos_test/src/main.cpp:257 > [0]PETSC ERROR: PETSc Option Table entries: > [0]PETSC ERROR: -pc_hypre_type boomeramg (source: command line) > [0]PETSC ERROR: -pc_type hypre (source: command line) > [0]PETSC ERROR: -use_gpu_aware_mpi 0 (source: command line) > > Do I have to use a separate PETSc/HYPRE build to do the CPU/GPU > comparisons? > Yes, that is the case for now. Hypre recently added preliminary support for running CPU/GPU tests with a single build. I did some experiments in petsc with it. I got rid of the error you showed, but failed to have the expected convergence rate. So, there are still bugs. > > I was also wondering if the base PETSc KSP solvers use any kind of GPU > acceleration, and if this is configurable at runtime. > Unlike Hypre, if petsc is configured with GPU support, it can run CPU-only tests (even on machines with GPUs) > > I tried solving a 2D poisson system, and whether I allocated CPU or GPU > vectors the KSP solver will complete in roughly the same non-trivial amount > of time, which makes me suspect that either it is never being solved on the > GPU or is always solved on the GPU since I'm only using a single CPU core. > This is with PETSC compiled with CUDA/Kokkos support. > You can add -log_view -log_view_gpu_time to compare the profiling result.
