Evaluation of two traffic distribution strategies for a dual-network multiprocessor system

The effect of nonuniform traffic patterns is studied based on simulation and analysis when two multistage networks are used in parallel to interconnect processors and memory modules in a shared-memory system. The networks considered are identical copies of buffered multi stage networks. The authors consider the following two strategies to distribute the total traffic between the two networks: distribute the traffic randomly among the networks, and route the nonuniform component of the traffic to one network and the uniform component to the other. To facilitate the implementation of these strategies in a system, a technique to detect nonuniformities in the network traffic at run-time and change the routing strategy dynamically is discussed. The authors compare this technique to an ideal scheme by means of analysis and simulation. The results show that the run-time detection scheme performs very close to the ideal case. The effectiveness of dual networks in tolerating short bursts of nonuniform traffic is also demonstrated