UNISM: Unified Scheduling and Mapping for General Networks on Chip

Task scheduling and core mapping have a significant impact on the overall performance of network on chip (NOC). In this paper, a unified task scheduling and core mapping algorithm called UNISM is proposed for different NOC architectures including regular mesh, irregular mesh and custom networks. First, a unified model combining scheduling and mapping is introduced using mixed integer linear programming (MILP). Then, a novel graph model is proposed to consider the network irregularity and estimate communication energy and latency, since the number of network hops is not accurate enough for irregular mesh and custom networks. To make the MILP-based UNISM scalable, a heuristic is employed to speed up our method. Compared with two previous state-of-the-art works, experimental results show that more than 15% and 11.5% improvement on the execution time is achieved with similar energy consumption on average for regular mesh NOC. For irregular and custom NOC, the improvement is 27.3% and 14.5% on the execution time with 24.3% and 18.5% lower energy. Moreover, our method is scalable for large benchmarks in terms of runtime.