On-Chip Decentralized Routers with Balanced Pipelines for Avoiding Interconnect Bottleneck

Abstract

Technology scaling makes designers face difficulties dealing with wire delay of long global interconnects, especially for high-radix networks. In this context, we propose decentralization of on-chip packet routers. A decentralized router consists of submodules, each of which has particular functionality and they are scattered on a link, thereby long wires are segmented. Our starting point is from a conventional router architecture, and we illustrate four case studies to generalize our proposal. We also propose a new buffer design and how to balance pipelines of a router. A proof-of-concept is shown in 28-nm process technology. Our results demonstrate that the decentralization of an on-chip router enables Link Traversal (LT) stages to be eliminated, and the critical path delay is improved by up to 45% with the reduced area compared with a conventional router. As technology advances, the benefit of the decentralized routers become more substantial in the nano-scale era.