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From: Galen Shipman (gshipman_at_[hidden])
Date: 2006-02-08 17:16:45


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