[Beowulf] Problems with a JS21 - Ah, the networking...

[Alan Louis Scheinine]

I found that the blocking send of MPI blocks for the
version of MPICH compiled for Myrinet (at least w.r.t.
the old GM) but does not block for the MPICH from
Argonne compile for GCC and PGI.  Or was it the other
way around, I don't recall.  Assuming it was the first
case, it might be relavent.  Someone wrote a program
that had deadlock, a simple  send() ; recv(); in the
same order for two processes will cause deadlock.  But the
program ran always until he changed the connection
and hence the underlying drivers.