Traffic Driven Automated Synthesis of Network-on-Chip from Physically Aware Behavioral Specification

The process of laying out the various interconnect components and configuring them, is termed as interconnect synthesis. A Network-on-Chip (NoC), has various building blocks such as Routers, Resizers, Power and Clock domain converters (PCDCs), Pipeline elements etc. A software tool is needed to connect these various components (topology) and then configure them (including routing) so that the user constraints are met and the overall logic and wiring cost along with power is kept low. In this paper we present a tool which generates Power, Performance and Area (PPA) optimized NoCs. The input is a behavioral specification which consists of a rough floor-plan, bridge parameters, available clock, power and voltage domains, address spaces, stochastic traffic (including classes and latency criticality), traffic dependency and any partial topology for the locked down portions of the NoC. The output is an optimized NoC, with instantiation and placement of components (routers, Resizers etc.), Virtual Channel (VC) assignments, clockdomain assignments, routing, bridge parameter tuning, FIFO sizes etc. Using this flow, we are able to generate NoCs which are within 15% of the hand-tuned designs (optimized over several months), for various metrics and exceed critical metrics by as much as 30%.