An Effective Throttling Method Based on Quasi-global Congestion Information

A massively parallel computer involves a large number of routers that are independent of each other. Adaptive routing methods offer high levels of flexibility in packet routing, but their performance is limited due to their locality nature. The Cross-Line method handles quasi-global information of congestion to improve performance. This paper introduces two new ideas of adaptation level and evaluation function into the Cross-Line method to discuss further enhancement. Based on the discussion, we propose the Cross-Line throttling that employs the Cross-Line mechanism to do an effective and low-cost throttling. Throughput the discussions in this paper, we use a quantitative evaluation methodology, and we introduce packet types for clear analysis. With the evaluation method and tool, we present novel and clear views of adaptive routing methods, and also present effectiveness of the proposed throttling method.