嵌入式系统中基于PCM/DRAM混合型内存的能耗和耐久性优化技术研究

Non-volatile memory techniques have emerged to attract extensive attention from industry and research community. Among all emerging non-volatile memory techniques, PCM is one of the most promising because of its high density, low power consumption, fast access speed and non-volatility. Hybrid PCM/DRAM main memory has been proposed to utilize the advantages of both types of memory. However, the high write energy consumption and low endurance of PCM has long been an obstacle towards replacing traditional DRAM memory by using hybrid memory due to performance and reliability concerns. In application-specific embedded systems with limited hardware resources, how to effectively utilize hybrid PCM/DRAM main memory, and mitigate the negative effects introduced by PCM, for reducing energy consumption and improving endurance becomes an important research issue. This project targets at hybrid PCM/DRAM main memory based application-specific embedded systems, and tries to meet goals in energy consumption and endurance. The above goals will be achieved by building energy consumption model, proposing energy-aware data placement technique. Based on application-specific energy-aware data placement technique, we will further study energy-aware metadata placement technique and segment-based application-specific wear leveling for improving PCM endurance. The results of this project will provide new directions for optimizing hybrid PCM/DRAM main memory in embedded systems in terms of energy consumption and endurance.

新型非易失性存储器的快速发展已得到广泛关注。其中，相变存储器（PCM）凭借其存储密度高、静态功耗低、存取速度快和非易失性等优点，与DRAM融合组成混合型内存正推动着存储技术的发展。然而，PCM写能耗高和耐久性低的问题，为混合型内存的性能及可靠性带来挑战。在面向特定应用及资源受限的嵌入式系统中，如何有效利用PCM/DRAM混合型内存及其优势，降低PCM对系统能耗和耐久性的负面影响，是亟待解决的重要问题。本项目结合能耗、耐久性等嵌入式系统关键指标，开展基于PCM/DRAM 混合型内存的可靠性和耐久性研究。通过建立能耗优化模型，设计面向嵌入式系统特定应用的能耗感知的数据分布优化技术，并在此基础上开展以低能耗为目标的元数据分布优化和基于区段的耐久性优化研究。本项目的成果将为嵌入式系统中PCM/DRAM混合型内存的能耗及耐久性优化提供新思路，为混合型内存在嵌入式系统中的高效应用提供技术支撑。

近年来，新型非易失性存储器的快速发展已得到广泛关注。其中，相变存储器（PCM）凭借其存储密度高、静态功耗低、存取速度快和非易失性等优点，与DRAM融合组成混合型内存正推动着存储技术的发展。然而，PCM写能耗高和耐久性低的问题，为混合型内存的性能及可靠性带来挑战。在面向特定应用及资源受限的嵌入式系统中，如何有效利用PCM/DRAM混合型内存及其优势，降低PCM对系统能耗和耐久性的负面影响，是亟待解决的重要问题。..本项目结合能耗、耐久性等嵌入式系统关键指标，开展了嵌入式系统中基于PCM/DRAM 混合型内存的可靠性和耐久性研究。通过建立能耗优化模型，项目组开展了基于非易失性存储器的嵌入式系统交换分区优化技术，面向嵌入式系统特定应用的能耗感知的数据分布优化技术，以低能耗为目标的元数据分布优化和磨损均衡及耐久性优化研究等研究工作。通过仿真验证，项目成果有效提升了嵌入式系统中基于PCM/DRAM混合型内存的寿命和性能。..通过上述研究，本项目的成果可以嵌入式系统中PCM/DRAM混合型内存的能耗及耐久性优化提供新思路，为混合型内存在嵌入式系统中的高效应用提供技术支撑。