> On Nov 11, 2014, at 17:13 , Jeff Squyres (jsquyres) <jsquy...@cisco.com> > wrote: > >> More particularly, it looks like add_procs is being called a second time >> during MPI_Intercomm_create and being passed a process that is already >> connected (passed into the first add_procs call). Is that right? Should >> the MTL handle multiple add_procs calls with the same proc provided? > > I'm afraid I don't know much about the MTL interface. > > George / Nathan?
The Intercom_create is a funny function, as it can join together two groups of processes that didn’t knew each other before. Thus, we have to be conservative in the upper level of the function and provide the entire list of [potentially] new processes to the PML/MTL to add to their known processes. In the case of the PML, this list is then forwarded down to the BTL, where only the new processes are added. Thus, the BTLs support adding multiple time the same process. I think a similar mechanism should be added to the MTL. If the process is already known, just mark it as reachable and be done. George.
