The Real-Time Analyzing And Improving For An Embedded Operating System

With the development of the embedded system technology, the real-time performance is required higher and higher. As the embedded operate system is the key of embedded system, the real-time problem about the embedded OS become the research focus, so it is significant to research that problem.The real-time theory of the embedded OS is researched in the paper, and then the μC/OS-Ⅱ is selected as the research object. Through analyzing the system structure of μC/OS-Ⅱ, we can find some problems of real-time in the μC/OS-Ⅱ, and then the solution is put forward to solve those problems.μC/OS-Ⅱ can be optimized in three aspects, such as the scheduling, the time and interrupt management and the memory management. The problem in the scheduling and time management can be solved by the optimizing method that is put forward in the paper, and the problem in the memory management is also discussed and summarized in the paper.1) In the scheduling, the methods that reduce the priority inversion are improved. μC/OS-Ⅱ provides mutex to reduce priority inversion problem, which is based on the priority ceiling. This makes application programs complex and the developers still have some difficulties in programming real time applications with it. So the module based on the priority inheritance is added to the μC/OS-Ⅱ kernel.2) In order to solve the problem in the time and interrupt management, the ATR module is added to the μC/OS-Ⅱ kernel. In the μC/OS-Ⅱ, it provides the periodic timer interrupt. When the timer ISR execution, the OS should modify or compare waiting valuables of all waiting tasks to check the expiration of the waiting time. And if the higher priority task is ready, the OS make it running, so which makes some problems on many real-time applications. Then the Adjustable Timer Resolution (ATR) algorithm is proposed to solve those problems. ATR can prevent useless timer interrupt occurring to save CPU time and enhance the OS execution performance.In the paper, some algorithms are analyzed and implemented, and the correlative module is added to the OS kernel. Each module has a variable that control the module can be translated and edited or not. If the module must be used, the variable is settled 1,...