A Research Of Scheduling Method Based On The Real-Time Linux

Real-time systems are mainly designed to satisfy the timing requirements from the real word application. A real-time system concerns not only the logic correctness of the computing results, but also the time when the results come out. Nowadays, real-time systems have been widely used in military and civilian industry. However, with the development of real-time systems application, the case that the different kinds of hard real-time and soft real-time application coexist in one system become more and more popular. This situation brings new opportunity and challenge to the research of real-time scheduling in the real-time systems.This thesis presents the author's work in research of the theory and method of real-time scheduling for his master degree. Most of the thesis focuses the method of real-time scheduling which can supports both hard real-time and soft real-time tasks.Firstly, the scheduling problems for real-time systems are discussed and an integrated scheduling frame which is based on the theory of real-time scheduling of server based is proposed. It introduces a multi-layer scheduling strategy and can support more kinds of realtime scheduling algorithms. Compared with the approaches already existing, the multi-layer scheduling strategy can support more kinds of scheduling objects. Further more, it can separate various real-time scheduling algorithms from the distribution of processor bandwidth, satisfy various real-time applications requirements and be extended easily. Therefore, it fits the realtime systems better which the different kinds of real-time application coexist in.Then a scheme is designed for implementing the integrated schedulmg level in a kind of real-time Linux kernel. This scheme is based on a double-kernel structure and basic priority scheduling. It combines the integrated scheduling frame and the functions of the Linux kernel;consequently, it can support the scheduling of real-time systems.In the last part of this thesis, we designed an experiment scheme using the implemented system in Linux environment. The results from the experiment show that the hard real-time andsoft real-time tasks can be integrated and scheduled, and the aim of supporting many kinds of real-time applications for the real-time systems in one processor is achieved...