Impact of Resource Sharing and Register Retiming on Area and Performance of FPGA-based Designs

Due to the increasing diversity and complexity of embedded systems, the use of high-level synthesis (HLS) and that of FPGAs have been both becoming prevalent in order to enhance the design productivity. Although a number of works for FPGA-oriented optimizations, particularly about resource binding, have been studied in HLS, the HLS technologies are still immature since most of them overlook some important facts on resource sharing. In this paper, for FPGA-based designs, we quantitatively evaluate effects of several resource sharing approaches in HLS using practically large benchmarks, on various FPGA devices. Through the comprehensive evaluation, the effects on clock frequency, execution time, area, and multiplexer distribution are examined. Several important discussions and findings will be disclosed, which are essential for further advance of the practical HLS technology.