Study Of Real-time Based On Embedded Linux Operating System

Real-time operating system was the soul of the embedded system, and had been widelyused in the higher real-time demand embedded fields such as communications、industrialcontrol、military defense and so on. General operating system only focused on the systemaverage performance. As for the whole system, the average response time of all task was thekey. Compared with general operating system, the correctness of the real-time operatingsystem depended not only on the logical result of the calculation, but also on the calculationresults from the time. As one of the open source software, with its source code open, free andcompatible with Unix、strong network function、the kernel that could cut、support for a varietyof system structure and stable performance and so on, Linux operating system was quicklyinto the embedded real-time system field. Although Linux2.6provided some real-time support,such as O(1)scheduler、preemptive kernel and so on, it was after all a timesharing system,still could not satisfy the most embedded real-time system requirements. Hence, in order to letLinux operating system meet the real-time requirement of the embedded system, it wasnecessary to optimize Linux2.6kernel.To Linux2.6kernel for research foundation, this paper analysed the clock mechanism、the process scheduling mechanism and the kernel synchronization mechanism of Linux2.6kernel in depth. In order to improve the real-time performance of the system, this paper putforward two improvement plans. According to the rough clock particle size of Linux2.6kernel,the article proposed a kind of Linux based on the real-time clock APIC improvement method,making the system achieve a microsecond clock precision through the APIC clock for lesschange. According to the critical area that a lot of spinlocks protected, that could not bepreempted, this article put forward a kind of solution with exclusive lock replacing spinlock,making the real-time tasks get timely response and improving the real-time of the system.Finally, through the test, the real-time of Linux2.6kernel after two kinds of improvementschemes had been improved largely, more meeting the requirements of the embedded systemin real-time.