Onion: An Efficient Heuristic for Designing Routerless Network-on-Chip
Jie Xiao, Kwan Lawrence Yeung · 2019
In routerless network-on-chip (NoC), any pair of cores are directly connected via at least one isolated ring, such that high-cost routers can be entirely abandoned. In this paper, we focus on the problem of designing a set of rings that guarantee the connectivity and minimize the average hop count for all core pairs in an n×n chip multiprocessor. Following an outside-in layered approach, a novel algorithm called Onion is proposed. In Onion, a set of square rings are recursively generated to realize routerless NoC. We prove that Onion guarantees the core-to-core connectivity with the minimum number of links between adjacent cores. To further improve its performance and at the cost of an extra link between adjacent cores, an extended algorithm called Onion+ is also proposed. Extensive numerical results show that both Onion and Onion+ perform increasingly better than RLrec, the current state-of-the-art algorithm, as n increases.