A lightweight metric for the evaluation of network congestion in NoC-based MPSoC

An effective run-time application mapping algorithm needs to reduce network congestion due to its significant impact on network performance. In this paper, we propose a lightweight congestion evaluation metric for application mapping algorithms in NoC-based MPSoC. We obtain information from task graphs and the mapping results, and use it to calculate a congestion metric to evaluate the link interference for a given communication flow. The congestion metric is the number of flows which share the same link with the given flow, it reflects both internal and external congestion. The congestion metric is accurate and lightweight, it can be used in runtime application mapping algorithms and other real-time tasks. Simulation result shows a strong correlation between the metric value and the average latency. Compared with other similar metrics, our congestion metric shows much greater accuracy.