Lw-PTP:面向MCU的轻量级精确时钟同步协议实现技术  

Lw-PTP:Implementation Technology of Lightweight Precision Clock Synchronization Protocol for MCUs

作　　者：胡小君 李成龙 王莎 李韬[1] 李存禄 HU Xiaojun;LI Chenglong;WANG Sha;LI Tao;LI Cunlu(School of Computer,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学计算机学院,长沙410073

出　　处：《小型微型计算机系统》2024年第5期1150-1156,共7页Journal of Chinese Computer Systems

基　　金：国家重点研发计划项目(2018YFB1800402)资助。

摘　　要：在嵌入式网络系统中,实现精确的时钟同步对于事件排序、实时通信、同步采样和驱动等应用至关重要.PTP作为IEEE1588标准定义的精确时钟同步协议,因同步精度高、稳定性好等特点逐渐成为嵌入式网络系统的主流支持协议.然而,嵌入式网络系统因成本、体积和功耗等方面的约束,其核心部件—微控制器(MCU)的计算和存储资源有限.现有PTP协议并未专门针对嵌入式网络系统进行定制优化,在部署时可能会超出部分MCU的计算和存储资源上限.针对上述挑战,本文提出了一种面向MCU的轻量级精确时钟同步协议实现技术—Lw-PTP,采用共享存储机制减少数据处理过程中的拷贝,并使用移位操作实现的近似计算处理替换部分精确计算处理,从而减少对计算和存储资源的占用.实验结果表明,在相同条件下,Lw-PTP相比于与传统PTP实现,能够降低至少20%的存储资源开销和至少60%的计算资源开销,同时仍然能够实现数十纳秒级高精度时钟同步.In embedded networking systems,accurate clock synchronisation is critical for applications such as event sequencing,real-time communication,synchronous sampling and driving.PTP defined by the IEEE1588 standard is a clock synchronization protocol,with high synchronization accuracy,good stability and other characteristics,and has gradually become one of the mainstream protocols supported by embedded network systems.However,embedded network systems have limited computing and storage resources for the core components,microcontrollers unit(MCUs),due to cost,size and power constraints.the original PTP protocl has no optimised or customized design for embedded networking systems.The implementation of original PTP may exceed the upper bound of computing and storage resources of some MCUs.To sovle the above problems,this paper proposes a lightweight precision clock synchronization protocol implementation technique named Lw-PTP for MCUs.Lw-PTP uses a shared storage mechanism to reduce copying during data processing and replaces some of the precision computational processing with approximate computational processing implemented by shift operations,reducing the consumption of computing and storage resources.Experimental results show that,compared with the original PTP implementation under the same conditions,Lw-PTP can reduce storage resource overhead by at least 20%and computing resource overhead by at least 60%,while still achieving dozens of nanosecond level clock synchronization.

关 键 词：嵌入式网络系统 IEEE1588 微控制器 共享存储 移位操作 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]