Throughput optimization for two-dimensional mesh and torus networks

DaeHo Seo, Purdue University

Abstract

Two dimensional networks constitute an important class of interconnection networks in both commercial and research machines. Minimizing latency and maximizing throughput are important design goals. In this thesis, I propose three techniques to improve the throughput achieved in two-dimensional mesh and torus networks. First, the routing algorithm may create an imbalance in the load on network links. Ideally, I would like a routing algorithm to (a) route packets using the minimal number of hops, (b) deliver good worst-case and average-case throughput, and (c) enable low-complexity router implementation. Existing routing algorithms fail to satisfy one or more of design goals mentioned above. We propose a new routing algorithm - O1TURN - satisfying all the stated design goals. Second, crossbar arbitration may underutilize free output ports and thus unnecessarily degrade throughput. The performance of crossbar arbitration depends on two metrics:(a) matching power, (b) arbitration throughput. Unfortunately, these two metrics are conflicting goals to achieve. I propose new crossbar arbitration mechanism - TabArb - that delivers superior matching and high arbitration throughput. It improves the saturation throughput by 14.8%. Third, I address network switching for streaming communication. Unfortunately, traditional packet-switched networks are not suitable for streaming communication. In packet-switching, each packet contends for resources as it traverses the network which can result in significant throughput degradation for streaming applications. I demonstrate a disjoint-path routing that ensures that streaming data has dedicated bandwidth. It improves the throughput of streaming applications by 55% on a 4x4 mesh network.

Degree

Ph.D.

Advisors

Thottethodi, Purdue University.

Subject Area

Electrical engineering

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