A Low-Overhead Interconnect Architecture For Virtual Reconfigurable Fabrics

Field-programmable gate arrays (FPGAs) have been widely shown to have significant performance and power advantages compared to microprocessors and graphics-processing units (GPUs), but remain a niche technology due in part to productivity challenges. Although such challenges have numerous causes, previous work has shown two significant contributing factors: 1) prohibitive place-and-route times preventing mainstream design methodologies, and 2) limited application portability preventing design reuse. Virtual reconfigurable architectures, referred to as intermediate fabrics (IFs), were recently introduced as a potential solution to these problems, providing 100x-1000x place-and-route speedup, while also enabling application portability across potentially any physical FPGA. However, one significant limitation of existing intermediate fabrics is area overhead incurred from virtualized interconnect resources. In this paper, we perform design-space exploration of virtual interconnect architectures and introduce an optimized virtual interconnect that reduces area overhead by 48% to 54% compared to previous work, while also improving clock frequencies by 24% with a modest routability overhead of 16%.