A System-Level Cosynthesis Framework for Power Delivery and On-Chip Data Networks in Application-Specific 3-D ICs

Abstract

With increasing core counts ushering in power-constrained 3-D multiprocessor system-on-chips (MPSoCs), optimizing communication power dissipated by the 3-D network-on-chip (NoC) fabric is critical. At the same time, with increased power densities in 3-D ICs, problems of IR drops in the power delivery network (PDN) as well as thermal hot spots on the 3-D die are becoming very severe. Even though the PDN and NoC design goals are nonoverlapping, both the optimizations are interdependent. Unfortunately, designers today seldom consider the design of the PDN, while designing NoCs. Moreover, for each new configuration of computation core and communication mapping on an MPSoC, the corresponding intercore communication patterns, 3-D on-chip thermal profile, as well as IR-drop distribution in the PDN can vary significantly. Based on this observation, we propose a novel design-time system-level application-specific cosynthesis framework that intelligently maps computation and communication resources on a die, for a given workload. The goal is to minimize the NoC power as well as chip-cooling power and optimize the 3-D PDN architecture; while meeting performance goals and satisfying thermal constraints, for a microfluidic cooling-based application-specific 3-D MPSoC. Our experimental results indicate that the proposed 3-D NoC-PDN cosynthesis framework is not only able to meet PDN design goals unlike prior 3-D NoC synthesis approaches, but also provides better overall optimality with the solution quality improvement of up to 35.4% over a probabilistic metaheuristic-based cooptimization approach proposed in prior work.