Kurt, Yes, that is correct. Spawned processes should be sure to call MPI_COMM_DISCONNECT on their parent communicator before MPI_FINALIZE. Ken On 2/21/21, 4:13 PM, "Mccall, Kurt E. (MSFC-EV41) via discuss" <[email protected]> wrote: Hui, So are you saying that the worker can call MPI_Finalize and it won’t wait for the manager that spawned it to do the same? That would be ideal. Thanks, Kurt From: Zhou, Hui <[email protected]> Sent: Sunday, February 21, 2021 4:07 PM To: [email protected] Cc: Mccall, Kurt E. (MSFC-EV41) <[email protected]> Subject: [EXTERNAL] Re: Calling MPI_Finalize or not The worker should call `MPI_Finalize` before exit. If somehow it hangs, assuming all the resources have been freed/disconnected, it must be a bug, please file an issue and we’ll track it down. Each spawned process has a different `MPI_COMM_WORLD` from the process who spawned it. -- Hui Zhou From: Mccall, Kurt E. (MSFC-EV41) via discuss <[email protected]> Date: Sunday, February 21, 2021 at 3:06 PM To: [email protected] <[email protected]> Cc: Mccall, Kurt E. (MSFC-EV41) <[email protected]> Subject: [mpich-discuss] Calling MPI_Finalize or not Two questions: I have a group of manager processes, each of which uses MPI_Comm_spawn() to create individual worker processes one at a time. Occasionally, a worker has to exit and is replaced by another worker via MPI_Comm_spawn(). If the exiting worker calls MPI_Finalize(), will it sit there waiting for all other managers and workers in MPI_COMM_WORLD to do the same, or will it wait only for the manager that created its inter-communicator to call MPI_Finalize? In either case, maybe it is better for the worker to NOT call MPI_Finalize at all so that it doesn’t sit there taking up a core’s resources while it waits for the others. What are the implications of not calling MPI_Finalize in the workers? Thanks, Kurt