Live Webcast 15th Annual Charm++ Workshop

Petascale machines with hundreds of thousands of cores are being built. These machines have varying interconnect topologies and large network diameters. Computation is cheap and communication on the network is becoming the bottleneck for strong scaling of parallel applications. Most parallel applications typically have a certain communication topology. Mapping of tasks in a parallel application based on their communication graph, to the physical processors on the machine can potentially lead to performance improvements. Mapping of the communication graph for an application on to the interconnect topology of a machine while trying to localize communication is the research problem under consideration. Performance improvements for applications such as WRF and NAMD will be presented to motivate the work. Building on these ideas, the talk will discuss algorithms and techniques for automatic mapping of parallel applications to relieve the application developers of this burden. The automatic mapping framework is a suite of algorithms with capabilities to choose the best mapping for a problem with a given communication graph. This framework will save much effort on the part of application developers to generate mappings for their individual applications.