服务体执行流模型中消息通信的时间可预测性分析

Time Predictability Analysis for Communication Modules in Servant / Exe-Flow Model

Minicore是基于服务体执行流模型的新型微内核,它有效的将操作系统中的存储模型和运行模型相分离.微内核的高度模块化的设计使Minicore对服务体(Minicore的基本单元)间的消息通信的依赖度极高.于是对于Minicore操作系统的时间可预测性分析也无可避免的依赖于通信模块的时间可预测性.本文的工作即是通过计算Minicore通信模块的WCET,分析消息通信的时间可预测性,为未来实现时间可预测的通信机制并分析Minicore的时间可预测性提供基础.对通信模块的WCET分析计算采用静态WCET分析中的基于路径的算法,应用到Minicore系统的通信模块,包括四个阶段:提取目标代码片段,程序控制流分析,处理器特征分析和WCET计算.基于WCET计算结果本文定义配置相关的时间可预测性(CIPr)作为评估消息通信时间可预测性的指标.

Minicore is a new microkernel based on Servant / Exe-Flow Model, in which the execution model and the storage model are independent of each other. The highly modularity design of microkernel made Minicore rely heavily on the inter-servant communication module, because a servant is the basic unit of the operating system. As a result, in order to analyse its time predictability, it is inevitable to conduct a time predictability analysis for Communication Modules in Servant / Exe-Flow Model. In the thesis, we estimate the WCET of Minicore＇s communication modules and analyze its time predictability with the definition of ClPr （Configuration-Induced Timing Predictability）, providing data to support its future mechanism of timing predictability, and foundation for future work of time predictability analysis for Minicore. Static WCET analysis and a path-based algorithm have been adopted in our work. Applying to the communication modules in Minicore, the method includes four phrases： extract code snippets for each communication mode, analyse communication control flow, analyse processor features, and calculate WCET finally.