ompi icon indicating copy to clipboard operation
ompi copied to clipboard

Published 20 hours ago • verified publisher icon open-mpi

MPI 4: Improve implementation of MPI_COMM_TYPE_HW_UNGUIDED

Open jjhursey opened this issue 3 years ago • 0 comments

PR #10630 added support for MPI_COMM_TYPE_HW_UNGUIDED and MPI_COMM_TYPE_HW_GUIDED. It provides good support for "guided" mode but minimal support for "unguided" mode. It closed issue #9197

There are a few ideas for how to implement the "unguided" mode that needs some experimentation.

  • See this comment for an implementation tip.
  • MPICH implemented this using a fixed top-down strategy in this PR see the MPIR_Comm_split_type_hw_unguided function.
  • In the paper "Towards leveraging collective performance with the support of MPI 4.0 features in MPC" cite the used a bottom-up strategy (see Section 7.2)

jjhursey avatar Aug 08 '22 13:08 jjhursey