Efficient task placement and routing of nearest neighbor exchanges in dragonfly networks

Abstract

Dragonflies are recent network designs that are one of the most promising topologies for the Exascale effort due to their scalability and cost. While being able to achieve very high throughput under random uniform all-to-all traffic, this type of network can experience significant performance degradation for other common high performance computing workloads such as stencil (multi-dimensional nearest neighbor) patterns. Often, the lack of peak performance is caused by an insufficient understanding of the interaction between the workload and the network, and an insufficient understanding of how application specific task-to-node mapping strategies can serve as optimization vehicles.