Research On Linux Real-time Optimization Technology Based On Domestic Platform

Because the embedded field has higher requirements for the real-time performance of the operating system,the research on the real-time operating system has always been relatively hot.Compared with the general operating system,which focuse on the overall system average performance,real-time operating systems pay more attention to the average response time.The correctness of the RTOS logic depends not only on the correctness of the calculation results,but also on the timeliness of the calculation results.At present,the RTOS have been widely used in aerospace control,defense weapons,industrial automation,electronic communications and other fields.Because the Linux kernel can realize an independent and controllable operating system with the advantages of its open source code,kernel cropping,strong compatibility,stable performance,strong community support,and free access,it has become a popular choice in the embedded field.Although the Linux kernel provides real-time support,it only supports soft real-time and does not yet have hard real-time capability.Therefore,in order to realize an independent and controllable real-time operating system,the Linux kernel needs to be reformed in real-time on the basis of understanding the Linux kernel,so that the Linux operating system meets the real-time requirements.In this paper,we take the Linux3.10.84 kernel as the base of the research,make an in-depth analysis of the Linux scheduling mechanism,and analyze the implementation details of the Linux scheduling mechanism.Drawing on Ingo Molnar's real-time preemption patch,using Mutex,priority inheritance,interrupt threading,high-precision clocks,and other technologies,Linux solves the lack of real-time performance as a general operating system.In order to allow preempt-rt patch to better play its best performance on Loongson platforms,In this paper,we address the issue of preemp-rt patch without real-time processing of certain parts of the MIPS architecture.In addition,because the real-time scheduling strategy of Linux operating system can not guarantee the deadline of real-time tasks,in this paper,we implement a dynamic scheduling strategy based on the EDF algorithm on the Linux 3.10.84 kernel.The EDF scheduling algorithm as the optimal scheduling algorithm on the single core does not guarantee that the deadline of the EDF task will not be missed.Therefore,the EDF+CBS technology is used in this paper to ensure the independence of the tasks,thus ensuring that any task will not miss their deadlines because of other tasks.In order to adapt to the multi-processor SMP system,this paper extends the EDF algorithm.On the basis of guaranteeing the top-N EDF task execution priority,the EDF task can be smoothly migrated between cores to ensure load balancing.Finally,through testing,the improved Linux kernel not only implements the EDF real-time dynamic scheduling strategy,but also greatly improves the real-time performance and can meet the real-time requirements of embedded systems.