The Research On Linux Scheduling Mechanism Under The Multi-Core Architecture

With the rapid development of embedded system, Linux has been widely used in various fields, such as mobile phone, laptop computer, GPS, game machine and so on. Although different embeded device requires different Linux system to run, Linux task scheduler still plays a key role in the Linux system. As the version of Linux improves, so does the task scheduler and its founction changed from simple to complex.Computer is a kind of system, it contains both hardware and software. The entire performance of system can not be improved only by the change of hardware, it also depends on the support of the software. To bring the strong point of the multi-core processor into full play, the cooperation of the task scheduler is required.This paper studies the latest Linux system scheduler and its support for multi-core processors. At first, This paper did a comprehensive analysis of source code of the latest kernel version 2.6.35 scheduler to understand how the modules of the schudeler work. Then, The paper analyzed the process of the load balance module in the scheduler and its support to multi-core processor. At last, Linsched which had been configured with varying number of cores had been used to do a large number of experiment to simulate the behavior of the CFS scheduler, combined the experiment results with the principle of the scheduler to do a in-depth analysis, in the purpose of having a further understanding the features of the scheduler under the multi-core architecture. The paper studied two aspects of the performance of scheduler, throughput and reponse time to summarized the equation of performance and these two aspects. Then, A set of experiments was done to find how the two factors, numbers of the cores and schedule grannularity effect the performance of the scheduler. In the end, The paper proposed the method of optimized of CFS scheduler based on the former experiment result and practical application, then a set of experiments was done to prove the correctness of the advice. Experimental results show that the method proposed in this paper is feasible.