A Quantitative Analysis of Processor Memory Bandwidth of an FPGA-MPSoC

Abstract

System designers have to choose between a variety of different memories available on modern FPGA-MPSoCs. Our intention is to shed light on the achievable bandwidth when accessing them under diverse circumstances and to hint at their suitability for general-purpose applications. We conducted a systematic quantitative analysis of the memory bandwidth of two processing units using a sophisticated standalone bandwidth measurement tool. The results show a maximum cacheable memory bandwidth of 7.11 GiB/s for reads and 11.78 GiB/s for writes for the general-purpose processing unit, and 2.56 GiB/s for reads and 1.83 GiB/s writes for the special-purpose (real-time) processing unit. In contrast, the achieved non-cacheable read bandwidth lies between 60 MiB/s and 207 MiB/s, with an outlier of 2.67 GiB/s. We conclude that for most applications, relying on DRAM and hardware cache coherency management is the best choice in terms of benefit-cost ratio.