Building a large-scale direct network with low-radix routers

Communication locality is an important characteristic of parallel applications. A great deal of research shows that utilizing the characteristic will favor most applications. Aiming at communication locality, we present a hierarchical direct network topology to accelerate neighbor communication. Combining mesh topology and complete graph topology, it can be used to optimize local communication and build large-scale network with low radix routers. Analyzing the characteristic of hierarchical topology, we find the presented topology has high cost performance and excellent expandability. We also design two minimum path routing algorithms and compare them with Mesh, Dragonfly and PERCS topologies. The results show the saturated throughput of hierarchical topology is nearly 40% with uniform random trace and 70% with local communication model of 4K nodes. That indicates high scalability for applications with local communication and cost efficiency for uniform random trace.