Sorry, more questions to answer:
On the other hand I am not sure it could even work at all, as whenever
I
tried at run-time to limit the list to just one transport (be it tcp or
openib, btw), mpi apps would not start.
you need to specify both the transport and self, such as:
mpirun -mca btl self,tcp
This is a simple loopback and leaving it out may be the problem.
Either way, I'm curious if it's even worth trying and if there's other
cuts that can be made to shave off one us or two (ok, I'l settle for
1.5 :-) )
For Heroic latencies on IB we would need to use small message RDMA and
poll each peers dedicated memory region for completion.
Thanks,
Galen
