It uses nonblocking point-to-point by default since that tends to perform better and is less prone to MPI implementation bugs, but you can select `-sf_type window` to try it, or use other strategies here depending on the sort of problem you're working with.
#define PETSCSFBASIC "basic" #define PETSCSFNEIGHBOR "neighbor" #define PETSCSFALLGATHERV "allgatherv" #define PETSCSFALLGATHER "allgather" #define PETSCSFGATHERV "gatherv" #define PETSCSFGATHER "gather" #define PETSCSFALLTOALL "alltoall" #define PETSCSFWINDOW "window" PETSc does try to use GPU-aware MPI, though implementation bugs are present on many machines and it often requires a delicate environment arrangement. "Maeder Alexander" <almae...@student.ethz.ch> writes: > I am a new user of PETSc > > and want to know more about the underlying implementation for matrix-vector > multiplication (Ax=y). > > PETSc utilizes a 1D distribution and communicates only parts of the vector x > utilized depending on the sparsity pattern of A. > > Is the communication of x done with MPI-3 RMA and utilizes cuda-aware mpi for > RMA? > > > Best regards, > > > Alexander Maeder
