Throttling Control for Bufferless Routing in On-chip Networks

As the number of core integration on a single die grows, buffers consume significant energy, and occupy chip area. A bufferless deflection routing that eliminates router's input-port buffers can considerably help saving energy and chip area while providing similar performance of existing buffered routing, especially for low-to-medium network loads. However when congestion increases, the bufferless frequently causes flits deflections, and misrouting leading to a degradation of network performance. In this paper, we propose IRT(Injection Rate Throttling), a local throttling mechanism that reduces deflection and misrouting for high-load bufferless networks. IRT provides injection rate control independently for each network node, allowing to reduce network congestion. Our simulation results based on a cycle-accurate simulator show that using IRT, IRT reduces average transmission latency by 8.65% compared to traditional bufferless routing.