BTLs have "add_procs" functions. E.g., my own parochial interests are
with the sm BTL and there is a mca_btl_sm_add_procs() function. I'm
trying to get a feel for how likely it is that this function would be
called more than once. There is code in there to support the case where
it's called multiple times: e.g., don't just call it once during
MPI_Init, but again during program execution to add more processes.
Maybe we can do this the "multiple choice" method:
A) That code is in there for standard purposes (dynamically added
processes or something?) and is robust and routinely tested.
B) That code was in there because we had hoped to support this stuff
someday, but I'm not sure if it works. It's not really tested and
rarely used by our users. We should clean it up sometime so that we're
sure it's doing what it should.
C) That code was a fantasy we had when we first started coding this
stuff, and for sure there is no prayer of that stuff working properly
today or any time in the foreseeable future without major work. Come to
think of it, we'd be doing ourselves a service by ripping all that stuff