Optimization Of Realtime Scheduling Algorithm Based On Linux

The realtime operating system is widely used in many fields, which attracts more and more attention of people. In numerous realtime operating systems, operating systems basesd on Linux are popular to people for its opened source codes and stability. However, Linux is not a genuine realtime operating system, so its realtime capability must be improved. The improvement of Linux realtime capability is one of the hotspots in computer field.At present, among all the methods of improving Linux realtime capability, the primary way includes thinning clock granularity, enhancement of the preemptive characteristic of Linux kernel, improving the scheduling strategy of the realtime scheduling server etc. Processing scheduling algorithm is an important factor of influencing system realtime performance. Through comparison and analysis, the method of scheduling strategy of improving realtime scheduling server in Linux kernel to promote realtime feature was proposed in this paper.In this paper, the realtime scheduling strategy of Linux and realtime scheduling algorithms weres studied, and realtime scheduling strategy and realtime scheduling algorithms under Linux environment were analyzed. For the simplicity of scheduling algorithm that supported by Linux, the realtime application of Linux has much limitation. And second order scheduling strategy was proposed.The concept of the second order scheduling strategy is that user can assign the scheduling properties in the current task group through interface, and scheduling server chooses the corresponding scheduling server according to current scheduling properties; the real scheduling executed on real time task group is accomplished by the chosen scheduling server. This design of the second order scheduling strategy server: rate monotonic scheduling server, earliest deadline first scheduling server and sharing CPU scheduling server implements the second order scheduling strategy.Finally, the realtime performance and function of this theory are tested on RTAI_linux platform, and the test results show that the improved RTAL_Linux has the function of the second order scheduling algorithm, and the realtime performance of RTAL_Linux was enhanced with comparison to the previous one.