Time Management In Embedded Real-Time Operating System ARTs-OS

Embedded real-time operating system is a kind of special operating systems. When external events or data generate, it can accept and dealt with them quickly enough and the results can be used to control the production process or rapidly response to processing system. It can also assure all real-time tasks to work in harmony. More rigid response speed, time accuracy and reliability of the system are requested. At the same time, the hardware resources, such as memory space, are very limited which puts space and time in sharp opposition. Therefore, the design of an efficient and stable subsystem which could also save power, without a doubt, would determine the performance of the entire operating system.According to the features of Embedded real-time operating system, based on S3C2410 development board as the hardware platform, the design and implementation of the time management subsystem are systematically introduced, including real-time clock, system clock, timer, watchdog, and analysis and design of several functional modules. Through discussing the working principle of each module, based on S3C2410 development board as the platform, the details of the layered time wheels algorithm and the difference time chain algorithm are introduced and these two algorithms are compared. And then an optimized algorithm is brought out of, which effectively improves the performance of the timer. Second, a detailed discussion of the watchdog about the working principle and application skills is brought forward. A guarantee is provided for the stability of the entire operating system.Through comparing and testing of the system stability and performance of the timer, it has been found that the time management subsystem significantly improves the system performance. The average performance of the timer under various loads can be increased by many times. The precision, maximum scheduling time, CPU computation, time-consuming for increase or delete timer are significantly improved. And the watchdog could effectively make the system to recovery after a breakdown.