RUNoC: Re-inject into the Underground Network to Alleviate Congestion in Large-Scale NoC
Xinghao Zhu, Jiyuan Bai, Zifeng Zhao, Qirong Yu, Xiaofang Zhou, Gengsheng Chen · 2025
In modem high-performance systems, the demand for large-scale Networks-on-Chip (NoC) has grown rapidly. As NoCs are scaled up, the issue of network congestion becomes increasingly critical and complex to address. Existing researches utilize partition-based NoC and Two-Level Network (TLN) techniques to alleviate congestion in large-scale NoCs. However, most of these solutions have limitations concerning universality, hardware overhead and workload balancing due to their inherent complexity and design constraints. In this article, we propose RUNoC, a new partition-based TLN architecture consisting of a Main Network for normal transmission and a sparse Underground Network enabling fast transmission. A special hardware unit is designed and integrated into each Main Network Router to decide when a packet needs to be routed to Underground Network based on network congestion information and the distance to the packet's destination, thereby alleviating congestion in Main Network and ensuring a subtle load balance between the two networks. Additionally, RUNoC is further enhanced by Shared Row Buffers (SRBs) and specialized network interface to guarantee deadlock and livelock freedom. Evaluation results indicate that RUNoC improves up to 60% in performance compared to XY routing scheme and up to 34% in performance-area ratio compared to existing researches.