How to precisely measure performance of routing algorithm is an important issue when studying routing algorithm of network-on-chip (NoC). The degree of adaptiveness is the most widely used metric in the literature. However, our study shows that the degree of adaptiveness cannot precisely measure performance of routing algorithm. It cannot account for why routing algorithm with high degree of adaptiveness may have poor performance. Simulation has to be carried out to evaluate performance of routing algorithm.
In this paper, we propose a new metric of routing pressure for measuring performance of routing algorithm. It has higher precision of measuring routing algorithm performance than the degree of adaptiveness. Performance of routing algorithm can be evaluated through routing pressure without simulation. It can explain why congestion takes place in network. In addition, where and when congestion takes place can be pointed out without simulation.