The roce-bush router: a case for routing-centric dimensional decomposition for low-latency 3D noC routers

As 3D System-On-Chips (SoCs) come ever closer to becoming the standard for high performance ICs, 3D Networks on Chips (NoCs) have emerged as a key component in meeting performance constraints and ensuring power-efficiency. Among the proposed 3D router architectures, dimensionally-decomposed routers are widely accepted as an efficient solution to deal with the increased port count and the accompanying exponential power and area increases. All decompositions proposed thus far have however been dimensionally static, that is, they have set in stone a particular bias among the three dimensions. This paper presents a novel router with a routing-centric decomposition and virtual channel buffer sharing called the Roce-Bush router. To our knowledge, this is the first work that integrates routing-awareness in the context of dimensional decomposition and buffer resource allocation for NoC routers. Experimental results involving RTL level implementations of our router and synthesis at 45nm show that compared to a dimensional-agnostic decomposed router, the Roce-Bush router can achieve up to 14% better performance and 5% lower power.