Research And Implementation On Real-Time Performance Of Embedded Linux Operation System

With the rapid development of information technology and computer network, embedded system is more and more important. At present, embedded system has been widely used in science research, engineering, military and consumer electronic, etc. As the most important core of software in embedded computer system, the embedded real-time operating system should be the most important part of research in this filed. Compare from traditional operation systems, the embedded real-time operation system functions better on the real-time reactions and could make correct and real-time responses to the exterior affairs.The researchers of the embedded real-time operation system focus on the Linux because of its openness of original codes, its designs of loadable kernel module and high flexibility of kernel size. However, while the designers limit the application of Linux in real-time computing by means of time divided multi-tasks, the effective of real-time approaches shall be taken to satisfy the requirements of the embedded systems to the real-time functions.At first, the article introduces the conceptions, characteristics and developing history of the embedded system and embedded real-time operation system. Then we analyze the real-time mechanism of the Linux and fault factors of the real-time performance of the Linux kernel. The paper give rise to two methods to improve the real time performance of Linux kernel: interrupt threads, modified spinlock mechanism. Interrupt threads creates kernel threads for every non-critical IRQ and gives it different real-time priority, so the IRQ threads can be scheduled by kernel as normal process; modified spinlock can decrease non-preemptive critical region in kernel. At last, the authors also describe the implementation for improved scheme under version of 2.6 series. The modification is a successful effort to decrease the interrupt latency and preemptive latency.