Efficient Memory Management for NVM-Based Hybrid Memory Systems
Zhangling Wu, Peiquan Jin, Chengcheng Yang, Lihua Yue · International Journal of Control and Automation · 2016
Non-volatile memory (NVM)such as phase change memory (PCM) has emerged as an attractive type of next-generation memories.NVMcan be incorporated into memory hierarchy to solve the problems of current DRAM instorage density and energy consumption.NVM is byte addressable and its latency is close to main memory, it exhibits higher density and lower idle power consumption than DRAM.However, NVM haslimited write endurance and asymmetriclatency and energy consumption for read and write operations.Therefore, hybrid memory systems involving both NVM and DRAM have been proposed for better utilizing NVM and DRAM.In this paper, we present a novel hybrid memory management schemecalled W-HCLOCK (Write-aware Hybrid CLOCK) that aims to keep a high hit ratio and minimize writes to NVM.Particularly, we introduce the concept of Recent-Rewrite-Distance (RRD), and combine it with recency of write operations to estimate the write-hotness of pages.Then, weplacewrite-intensive pages in DRAM to reduce NVM writes.In addition, we keepadditional information about the writes to evicted pages to avoid unnecessary migrations between DRAM and PCM.We conduct simulation experiments on four synthetic traces and one real OLTP trace.The results suggest the efficiency of our proposal.