Take a look at https://petsc.org/release/faq/#what-kind-of-parallel-computers-or-clusters-are-needed-to-use-petsc-or-why-do-i-get-little-speedup
Check the binding that OpenMPI is using (by the way, there are much more recent OpenMPI versions, I suggest using them). Run the STREAMS benchmark as indicated on that page. Barry > On Oct 10, 2023, at 9:27 AM, Gong Yujie <[email protected]> wrote: > > Dear PETSc developers, > > I installed OpenMPI3 first and then installed PETSc with that mpi. Currently, > I'm facing a scalability issue, in detail, I tested that using OpenMPI to > calculate an addition of two distributed arrays and I get a good scalability. > The problem is when I calculate the addition of two vectors in PETSc, I don't > have any scalability. For the same size of the problem, PETSc costs a lot > much time than merely using OpenMPI. > > My PETSc version is 3.16.0 and the version of OpenMPI is 3.1.4. Hope you can > give me some suggestions. > > Best Regards, > Yujie
