The Optimization Technology And The Application Of The Two-level Scheduling Of Embedded Linux System

As one of the most important components of a computer, the operating system not only provide user-friendly interactive interface, but also ensure the proper operation through rational organizations and well distribution on hardware / software resources. Besides general-purpose operating system with essential features, the operating system used in embedded systems have emphasized on real-time characteristics. With the in-depth study of embedded systems, embedded real-time operating system has become the current hot research object. This thesis focuses real-time embedded systems, real-time transformations on the Linux operating system process scheduling are conducted to apply in the corresponding hardware processing platform. The specific contents are as follows.1)Through the brief analysis on the Linux kernel characteristics and comparisons with the popular real-time operating systems can be conclude the urgency and importance of this study. Studies on architecture and implementation mechanism of the Linux kernel and comparisons between several kind of real-time transformation methods are carried out to determine the final plan.2)A two-level scheduling policy is the speculations on the basic ideas of scheduling policy. First, the user chooses to schedule according to screening, and then perform a specific real-time scheduling by the selected scheduler. RTAI scheduling strategy is selected as a platform to achieve secondary scheduling, which makes up the disadvantage of too simple algorithm and expands its scope of applications. Through the settings of RM, EDF and IO scheduler to support the Rate Monotonic algorithm and the Earliest Deadline First algorithm and IO scheduling algorithm. This scheduling policy make up the signal defect of RTAI.3)Scheduler which based on second-order scheduling is generated at last. Before generation, the overall design scheme of the system should be designed. RTAI_Linux is selected as an experimental platform to modify the data structure and scheduling functions.4)Real-time scheduling of embedded Linux performance is tested and analyzed. Some embedded real-time operating system scheduling real-time key performance indicators which are recognized by industry are introduced. Then some specific analyses and measurements are conducted to draw the final conclusion.5) We use the Two-Leve Scheduling to solve the single defect of real-time scheduling and improve the performance of Image information acquisition system.