Exploiting off-chip memory access modes in high-level synthesis

Abstract

Memory-intensive behaviors often contain large arrays that are synthesized into off-chip memories. With the increasing gap between on-chip and off-chip memory access delays, it is imperative to exploit the efficient access mode features of modern-day memories (e.g., page-mode DRAMs) in order to alleviate the memory bandwidth bottleneck. Our work addresses this issue by: (a) modeling realistic off-chip memory access modes for High-Level Synthesis (HLS), (b) presenting algorithms to infer applicability of HLS with these memory access modes, and (c) transforming input behavior to provide further memory access optimizations during HLS. We demonstrate the utility of our approach using a suite of memory-intensive benchmarks with a realistic DRAM library module. Experimental results show a significant performance improvement (more than 40\%) as a result of our optimization techniques.