一种面向非易失性内存文件系统的数据读写粒度控制策略  

A strategy of data accessing granularity for non-volatile main memory file systems

作　　者：王盈 蒋德钧 熊劲[1,2] Wang Ying;Jiang Dejun;Xiong Jin(Advanced Computing System Laboratory,Institute of Computing Technology Chinese Academy of Sciences,Beijing 100190;University of Chinese Academy of Sciences,Beijing 100049)

机构地区：[1]中国科学院计算技术研究所先进计算机系统研究中心,北京100190 [2]中国科学院大学,北京100049

出　　处：《高技术通讯》2021年第7期692-704,共13页Chinese High Technology Letters

基　　金：国家重点研发计划(2016YFB1000302);中国科学院战略性先导科技专项(XDB44030200);北京市自然科学基金-海淀原始创新联合基金(L192038)资助项目。

摘　　要：数据读写是文件系统的重要操作。传统的文件系统基于磁盘设计,数据读写需要旋转磁头,因此数据读写慢。文件系统使用I/O调度层对读写操作进行拆分和合并,减少磁头寻道时间,提高系统性能。新型非易失性内存(NVMM)支持字节寻址和随机访问,文件系统可以直接使用内存指令进行数据操作。因此,现有的NVMM文件系统,如ext4-dax、PMFS和NOVA,不再考虑数据操作粒度的优化,直接按照文件数据的存储粒度(如4kB)在应用和文件系统之间传输数据。然而,文件系统中的数据读写性能仍然受到操作粒度的影响。本文分析了文件系统在真实NVMM硬件上的性能,发现大粒度操作会降低文件系统性能,并针对数据读写操作粒度提出了优化策略。实验结果表明,本文提出的优化策略使得NVMM文件系统性能提升30.1%。Data reading and writing are important operations of the file system.The traditional block file system is designed on disk,and the data read and write require moving the disk head.Therefore,data reading and writing are slow.The file system uses I/O scheduler layer to split and merge read and write operations to reduce disk seek time and improve system performance.The emerging non-volatile main memory(NVMM)supports byte-addressable and can be directly attached to memory bus.File systems can directly use the memory command to operate data,improving the performance.Therefore,the existing NVMM file systems,such as ext4-dax,PMFS and NOVA,no longer consider the data operations size,and they directly transfer data between the application and file system according to the storage size of the file data(4kB).However,the data read and write performance in the file system is still affected by the granularity of operations.The performance of file systems on real NVMM hardware is analyzed,it is found that large granularity operations reduce the performance of the file system,and optimization strategies for data operation granularity are proposed.The experimental results show that these strategies can improve the performance of NVMM file system by 30.1%.

关 键 词：非易失性内存(NVMM) 文件系统 性能 数据读写粒度 

分 类 号：TP333[自动化与计算机技术—计算机系统结构]