An Efficient Row Buffer Policy Based on Per-Row Activation Counts

Abstract

An important role of the memory controller is deciding whether to keep a DRAM row open or close it after each access. Conventional open-page and close-page policies are simple but cannot adapt to dynamic memory access patterns which leaves room for performance optimization. Hybrid policies improve adaptability but their need to maintain multiple statistics tracking counters introduce high hardware overhead, especially as DRAM capacity grows. To address this limitation, we propose PRACOpen, a lightweight row buffer policy that uses preexisting per-row activation count (PRAC) data in DDR5 DRAMs as a heuristic to inform row buffer management decisions. We evaluate the performance of PRACOpen by comparing it against the two conventional row buffer policies using a simulated computer system with benchmarks from the SPEC CPU2017 suite. Our evaluation shows that PRACOpen achieves performance gains while keeping hardware overhead low.