A Research On The Methodology To Improve And Test Embedded Linux Real-time Performance

As embedded systems are widely applied, the demand for embedded operating systems is getting bigger. Compared to traditional commercial embedded operating systems, Linux is free, open-source, and powerful. Thus, more and more organizations and persons are applying Linux into embedded field. However, to be more influential in this field, Linux still has to improve in some aspects such as its compactness and real-time performance.At present, there are two main methods to make Linux real-time: dual kernel or direct modification of Linux kernel. And this paper put the focus on the dual-kernel RTAI real-time solution. At first, this paper introduced some theories and technologies related to the methodologies to improve Linux real-time performance, including some basic concepts of RTOS and Linux kernel, and the causes of Linux real-time problem. Later this paper put the emphasis on stating the architecture, rationale and key techniques of RTHAL-based RTAI. And based on practices, the steps and notes on how to build real-time Linux with RTAI were summarized. Next, this paper discussed the Adaptive Domain Environment for Operating Systems (ADEOS), which is to replace the Real Time Hardware Application Layer (RTHAL), and based on the test of ADEOS and RTHAL, this paper compared them in several aspects.Moreover, through practice and study, this paper found that there are no general programs that can not only test exactly the real-time performance of Linux improved by dual-kernel method, but also that of standard Linux. Thus, this paper designed and implemented a general program to measure Linux timer jitter based on Linux module programming. And in the end, this paper tested RTAI and standard Linux, and proved the correctness of the program by results.