[Question] Buffered mode

[dutkalex]

Hi! I notice that the CommMode enum does not include the buffered mode. Is this intentional or just an oversight?
Best regards,
Alex

[dssgabriel]

This is intentional (see related PR), as the Buffered communication mode requires manual buffer attachment from the user through MPI_Buffer_attach().
As our currently targeted applications do not need support for buffered communications, we just dismissed it.

We're currently thinking about adding functions for initializing, finalizing and, more generally, managing KokkosComm; this may change soon.

[devreal]

For the record: MPI 4.1 added MPI_COMM_ATTACH_BUFFER and MPI_SESSION_ATTACH_BUFFER to limit the scope of buffers to a communicator or session. It also added MPI_BUFFER_AUTOMATIC to enable automatic buffer allocation. Not sure what the implementation status is but this would be useful here once its provided.

[dssgabriel]

Indeed, especially if we want to go the MPI_Session route. I am going to look into it, thanks @devreal.

[dutkalex]

The argument makes sense. Thanks for the answer 🙃
(You can close the issue if you wish)