A Dynamic Row-Buffer Management Policy for Multimedia Applications

The DRAM-based main memory performance is lagging far behind the performance of modern processors. Achieving the highest possible performance of memory-bound applications on modern processors has been increasingly limited by the average DRAM memory access latency. The employed page policy, also referred to as a row-buffer management policy, has a significant impact on DRAM performance. Modern DRAM-based main memory systems have mainly two-page policies; Closed Page Autoprecharge (CPA) policy and Open Page (OP) policy. The optimal page policy is an application-dependent, hence a static page policy utilization may not always be the perfect choice to provide the lowest possible average DRAM memory access latency for the memory requests. In this paper, a dynamic page policy is proposed, in which the decision to switch between the OP policy and the CPA policy is made at run-time for each memory request through monitoring the memory access characteristics of the application instructions. The proposed approach aims at improving the DRAM bandwidth utilization and reducing the average DRAM memory access latency by lowering the number of time-consuming memory operations. The results obtained from this study revealed significant average Last Level Cache (LLC) miss penalty reduction of 25.8% when utilizing effectively the proposed approach compared to the baseline in the evaluated workloads.