Section: New Results

Process Placement and Topology-Aware Computing

Participants : Emmanuel Jeannot, Guillaume Mercier, François Tessier.

• TreeMatch 's limitations have been addressed. In particular, it is now able to handle unbalanced physical topologies.

• TreeMatch has been compared to various competitors. We carried out various experiments that showed that TreeMatch outperforms other solutions based on graph partitioning or graph embedding. These experiments also showed the limitations of some existing solutions (Scotch for instance).

• TreeMatch has been integrated into several major parallel programming environments. It is implemented as a load-balancer in Charm++ (François Tessier made severals at UI Urbana Champaign) and is used to enhance topology management routines in Open MPI and MPICH2. It is indeed employed to allow rank reordering in functions such as MPI_Dist_graph_create for instance. This work started with a visit at UTK by Guillaume Mercier .

• We set-up several collaborations: besides the collaboration with the Open MPI group, we also work with the CERFACS in order to speed-up existing CFD parallel applications developed by this group.