[Beowulf] choosing a high-speed interconnect

[joachim at ccrl-nece.de]

>    QP scaling isn't as critical an issue if the MPI implementation sets
> up the connections as needed (kinda of a lazy connection setup).  Why
> set up an all-to-all QP connectivity if the MPI implements an all-to-all
> or collectives as tree based pt2pt algorithms.  Network congestion on

Good MPI collectives often are not tree based, but need more connectivity.
Of course, the best collectives are optimized for a certain interconnect.

 Joachim