OD3P: On-Demand Page Paired PCM

Abstract

With current memory scalability challenges, Phase Change Memory (PCM) is viewed as an attractive replacement to DRAM. The preliminary concern for PCM applicability is its limited write endurance that is highly affected by process variation in nanometer regime. This increases the variation in cell lifetime resulting in early and sudden reduction in main memory capacity due to wear-out of few cells. When some memory pages reach their endurance limits, other pages may be far from their limits even when using a perfect wear-leveling. Recent studies have proposed redirection or correction schemes to alleviate this problem, but all suffer from poor throughput or latency. On contrary, we present On-Demand Page Paired PCM (OD3P), a technique that mitigates the problem of fast failure of pages by redirecting them onto other healthy pages, leading to gradual capacity degradation. Compared to a state-of-the-art error correction scheme for PCM, our experiments indicated that OD3P can improve PCM time-to-failure and system performance (IPC) by 12% and 14%, respectively, under multi-threaded and multi-programmed workloads.