Prior to this commit we matched local interfaces to remote interfaces in
order to create endpoints in a simplistic way. If any remote interfaces
were on the same subnet as any of our local interfaces then only local
interfaces would be paired (IP-routed remote interfaces would be
ignored).
This commit introduces a more general scheme which attempts to make the
"best" pairing of local interfaces to remote interfaces. We now cast
the problem as a graph theory problem known as the "Assignment Problem",
or finding a maximum-cardinality, minimum-weight bipartite matching. We
solve this problem by reducing the bipartite graph of interface
connectivity to a flow network and then solving for a minimum cost flow.
This is then easily converted into back into a matching on the original
bipartite graph.
In the new scheme, interfaces on the same subnet are preferred over
interfaces requiring intermediate routing hops and higher bandwidth
links are preferred over lower bandwidth links.
Reviewed-by: Jeff Squyres <jsquyres@cisco.com>
cmr=v1.7.5:ticket=trac:4253
This commit was SVN r30849.
The following Trac tickets were found above:
Ticket 4253 --> https://svn.open-mpi.org/trac/ompi/ticket/4253
c40f8879c8