Research On Embedded Linux And Its Scheduling Policy

With the rapid progress of information and networking technologies, the development of embedded systems, as one of the most important IT industries for the 21st century, will possess numerous commercial markets. In this situation, Linux system which has made great success in server applications will obtain further development and find wide applications in the embedded industry, with the advantages of low cost, powerful functions, and etc. The research on embedded Linux systems has recently received many attentions and become very active.In this thesis, we will investigate the real-time strategy and scheduling algorithms for embedded Linux systems. Some basic concepts and principles of embedded real-time Linux systems are first introduced, followed by an overview of its current research status. Then the issues that lead to the limited real-time operations and the corresponding solutions are discussed. In Chapter 2, we focus on the kernel preemption strategy and scheduling algorithms. For the kernel preemption, we will examine two improved schemes and patches, with emphasis on the analysis of the inserting-preemption-point scheme. With respect to the scheduling strategy, we will discuss the process schedule scheme used by Linux 2.4.18, as well as two classical algorithms for real-time scheduling. At the end of both Chapters 3 and 4 we explore the improved kernel aspects of the latest Linux version 2.6. In Chapter 5 a unified strategy for application-defined scheduling is presented based on the analysis of the schedule method adopted by Red-Linux.Finally, Chapter 6 summaries the main results presented in the thesis, and presents some future work related to the embedded Linux. A prospect of some possible developments in this direction is also provided.