Study On The Schedule Mechanism And Real Time Performance Of Linux

As a category of UNIX operating system, Linux obtains some features like stability and high efficiency which are features of UNIX operating system; meanwhile, the capabilities of Linux become more progress and mature. Compare with other operating systems, Linux can revise its source codes according to different demands, support some architecture platforms and customize some functions. These features make Linux have a potential prospect in real-time application.At the beginning of system design, Linux had not thought over the problem of real-time performance; hence kernel 2.4 and the earlier Linux versions cannot meet the demand of real-time application because the latency time of system is too long. For this reason, some work on these kernel versions have supported by numerous Linux programmers and research institutions. This work has an influence on enhancing the real-time performance of Linux. In kernel 2.6, the latest version, the improvements in real-time performance start a new era of Linux.Firstly, kernel 2.4 and kernel 2.6 have been analyzed; some methods and system workloads have been chosen to measure the real-time performance. Moreover, some authoritative methods that enhancing the real-time performance of kernel 2.4 have been try out to prove the measuring methods. By using the reference of these authoritative methods, the fundamental direction of improving the real-time performance of kernel 2.6 has been decided.Different from the others, some methods that enhancing the real-time performance of kernel 2.6 have been present from the integral angle and the partial angle. Distinct from some normal methods which usually focus on revising, adding and deleting some kernel source codes, a fresh method which uses the kernel module to preempt tasks in order to ensure the execute resolution of high-priority task has been presented. Other methods have linked up with some new features of kernel 2.6. The results show that on the same system workloads, the real-time performance has been improved in different degrees by these methods.