The Study Of A New Real-time Kernel Scheduling Algorithm

With the development of network technology, embedded systems and network communication technology combined with each other more and more closely. Embedded real-time operating system should not only meet requirements of real-time system but also to meet the network communication service quality. In the scheduling process of kernel, the system should not only rapid response system of real-time task, but also compatible with network transmission characteristics. The introduction of the network protocol stack based on embedded operating system has become the inevitable trend of the embedded system development.In this paper,we made a thorough investigation and study in kernel scheduling algorithm, conducted in-depth study of UCOS-II(MicroC/OS-II) embedded real time operating system, and propose a new kernel scheduling policy. The main contents are as follows:1) A new kernel scheduling algorithm was proposedThe new scheduling algorithm combined the advantages of Task Priority based scheduling algorithm and Time Slot Cycling based scheduling algorithm. The task ID was automatically managed, which provide a user-friendly interface. This algorithm effectively mitigate the defects of the original UCOS-II, which has only a few tasks, multiple tasks was not supported in the same priority level, and did not support priority inheritance, etc. Experiments showed that the efficiency of the new kernel scheduling algorithm has been significantly improved.2) UCOS-II's dynamic memory management strategy was improvedThe dynamic memory management strategy provided by UCOS-II is too simple to achieve high memory usage efficiency. This paper improved the dynamic memory management strategy of UCOS-II and implemented a size variable dynamic memory management strategy. Using this new strategy, the memory can automatically merge together after been released, which provides users with convenient and stable interface functions.3) Developed a network protocol stack for wireless meter reading system based on the new embedded kernelWe completed the new kernel porting, driver development and the underlying network protocol stack development based on hardware of wireless meter system. The entire protocol stack is divided into five layers, and it integrates with the traditional TCP / IP protocol.The network protocol stack implemented a network communication protocol which is compatible with IPv6, and capabilities of reliable data delivery, automatic networking and dynamic routing were achieved. After several tests, the system has good performance, fully meet the relevant national convention. In the network transmission environment, the new kernel has greatly improved the efficiency of the system.