[Swift-devel] Falkon and Coaster support for MPI

[Ben Clifford]

I had a brief look at how MPI runs inside PBS.

It looks something like:

 1.   user requests n nodes to run on PBS
 2.   PBS allocates those n nodes, and writes a description of them all 
      into a per-job (not per-node) $PBSNODEFILE
 3.   PBS runs the same mpi command-line on all of the nodes, specifying 
         $PBSNODEFILE somewhere in that command line.
 4.   The mpi commandline uses the $PBSNODEFILE to know how to get to all 
         the nodes.

It might not be too much change to the coaster code to make it so you can 
get this behaviour. You'd need to be able to specify a node count (rather 
than the implicit count of 1 at the moment) and have the coaster manager 
handle starting everything up at the same time and providing something 
like $PBSNODEFILE.

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