On the use of multiplanes on a 2D mesh network-on-chip

Abstract

Alike interconnection networks for parallel systems, Networks-on-chip (NoC) must provide high bandwidth and low latency, but they are further constrained by their on-chip power budget. Consequently, simple network topologies such as the 2D Mesh with shallow buffers and simple routing strategies such as dimensional order routing (DOR) have been widely used in order to achieve this goal. A low number of virtual channels could be used to eliminate head-of-line blocking and increase network throughput. Due to the spare routing area in deep submicron technology, another possibility is to replicate the simple network once or more times. This work compares and combines the two approaches, by considering the distribution of a fixed number of virtual channels over one or more multiplanes. A thorough evaluation of the possible 2D mesh network configurations under a range of workloads will show that, provided there is spare area, replicating the 2D mesh with 2 virtual channels results on the best power/performance trade-off.