一种基于访存行为地址映射机制的混合内存系统

Hybrid Memory System Using Memory Access-aware Remapping Mechanism

相变存储器(PCM)是一种高密度的新型存储器件,其数据读取性能与现有动态随机存储器(DRAM)相当且具有低功耗和按位寻址的特性,具备了替代DRAM的潜力,特别是应用在能量受限的移动计算系统中更能发挥优势.但是PCM在延迟和功耗方面存在读写不对称性,访问延迟大,写入功耗高且使用寿命受限.如何充分利用这一新型存储技术,通过存储结构的创新来实现计算机系统访存高性能和低功耗的目的,是研究的热点和重点.本文重点针对PCM的这些问题,提出了一种基于访存行为地址重映射机制MARM的PCM-DRAM混合内存系统.该内存系统将PCM和DRAM置于同一地址空间,以实时监测到的物理内存访问为基本依据,利用内存系统的物理地址重映射机制实现对PCM和DRAM物理页面的有效管理.实验表明,与传统的DRAM内存系统相比,基于MARM管理策略的PCM-DRAM混合内存系统可实现32%的功耗延时积收益.

As an advanced memory device with high density, Phase-change memory is comparable with DRAM in reading. So it is increasingly considered as a prevalent DRAM alternative due to its high density, low standby power and bit addressability, especially in the design of mobile computing systems with limited power supply. But long write latency, large write energy and limited endurance are becoming obstacles of PCM technology. An important concern for researchers is to achieve high-performance and low-power memory access according to the innovation of memory architecture using this new type of memory technology sufficiently. In this paper, we propose a Memory Access-aware Remapping Mechanism for PCM-DRAM hybrid memory system to tackle the above problems. This system places PCM and DRAM in the same address space and implements the management of PCM and DRAM physical page frame using address remapping mechanism, according to real-time monitoring of memory access pattern. Experiment results demonstrate an Energy-Delay Product （ EDP） improvement of 32% on average in MARM-based PCM-DRAM hybrid memory system, compared to conventional DRAM memory system.