VAIL: A Victim-Aware Cache Policy to improve NVM Lifetime for hybrid memory system

Abstract

Nowadays emerging Non-Volatile Memory (NVM) is introduced to remedy the shortages of current DRAM-based main memory, but limited write en-durance of NVM would severely restrict memory system. Many techniques are proposed to extend NVM lifetime based on DRAM and NVM hybrid memory. However, most of them cannot obtain satisfactory NVM lifetime and performance at the same time for various workloads, because they fail to deal well with the conict between reducing writebacks to NVM and improving DRAM access hit ratio. In order to solve this problem, we propose a Victim-Aware Cache Policy named VAIL for DRAM and NVM hybrid memory system. VAIL uti-lizes the property of victim pages to estimate and predict the impact of clean and dirty page replacement on writebacks to NVM and DRAM access hit ratio. Then, pick the page which has the minimal negative impact for replacement. By doing so, VAIL can reduce writebacks to NVM and achieve high DRAM access hit ratio simultaneously. It outperforms the state-of-the-art by 1.29x higher performance and leads to 11.7% less NVM wear-out, according to our evaluation with HPC, graph computing, and machine learning workloads.