Notes 2018 12 20

Participants

• Marc-Andre Hermanns
• Kathryn Mohror

Topics

MPI_T Events

• Take MPI_T_CB_REQUIRE_MPI_RESTRICTED out of hierarchy
  • It's a different kind of restriction that THREAD_SAFE and ASYNC_SIGNAL_SAFE
• List of restricted MPI functions stays as it is
  • MPI must support (at least) these in callbacks (but may choose to support more -> documentation)
  • MPI must support these for the highest requirement potentially raised
    • MPI handle alloc may be a problem ...
      • May be postponed until after callback (it's effectively non-blocking)
      • Info needs to available at postponed time if alloc is not perform in callback
      • deep copy of info would be needed but may be prohibitive if signal safety is required
      • No deep copy needed if info object defined to be read-only until first invocation of callback on allocated reg-handle (similar to send buffer)