Design Mode And Implement Approach Study For Solving Inversion Problem In μC/OS-Ⅱ

In project practice, embedded system often has very strong timely request, needs the embedded operating system to provide a better real-time support. Therefore, embedded operating system is generally a real-time operating system. Along with the application domain of embedded technology continuously expansion, Real-Time Operating System platform used to develop embedded application has obtained more and more widespread application, and the theories and technical problems related with Embedded Operating System have also become hot spot of research and development. Especially, to ensure real-time characteristics as well as resources effective management in Embedded Operation System have become the most important and the most active research topic in Operation System research domain. In preemptive and multitasking Real-Time Operation System, as a result of task subsequent execute as well as uses of shared resources, inevitable exists the danger of priority inversion which can affect the response time of high priority task. If does not take effective measures, infinite priority inversion may occur, application will collapse;At the same time, priority inversion is the unpredictable mistake's origin in application system. Therefore, it is crucial to alleviate priority inversion on Real-Time Operation System when analyzing and designing Embedded Real-Time System.In the paper, μC/OS-Ⅱ— a free code, preemptive and multitasking Real-Time Operation System has been selected as study object. Preemptive scheduling Kernel of μC/OS-Ⅱ has been anatomized;the reason and the influence produced by priority inversion phenomena have been analyzed detailed. Design models, being nominated as priority inheritence protocol and priority ceiling protocol which used to solve priority inversion, are researched and analyzed deeply. On the basis of above, application limit of priority inheritances protocol as well as application availability of priority ceiling protocol in μC/OS-Ⅱ are proposed and proved. Combined with μC/OS-Ⅱ's characteristics, definition of resources ceiling priority is improved;experimental model is designed;the solution scheme to solve priority inversion problem in uC/OS-II, which is similar to the priority ceiling protocol, is realized by employ μC/OS-Ⅱ's Mutex signal mechanism. The experiment simulation result indicated that, on the precondition of ensuringmutex visiting of the shared resources, the proposed approach limits the occurrence of priority inversion on one level, and alleviates the priority inversion phenomenon occurrence in uC/OS-n.Finally, a comment on specialties for realizing priority ceiling protocol to alleviate the occurrence of priority inversion in (iC/OS-E is given.