Priority assignment for real-time wormhole communication in on-chip networks

Wormhole switching with fixed priority preemption has been proposed as a possible solution for real-time on-chip communication. However, none of current priority assignment policies works well in on-chip networks due to some inherent properties of the protocol. In this paper, a novel heuristic branch and bound search algorithm is introduced to explore the possible priority ordering. Differing from the traditional exhaust algorithm which costs exponential complexity, our algorithm can effectively reduce the search space. In addition, this algorithm can ensure that if a priority ordering exists that makes the traffic-flows schedulable, this priority ordering will be found by the search algorithm. By combining with schedulability analysis, a broad class of real-time communication with different QoS requirements can be explored and developed in a SoC/NoC communication platform.