AN ADAPTIVE MULTI-LEVEL SCHEDULER ON μC/OS-II

• Main Authors: Yu-Chieh Li, 李育杰
• Other Authors: Liang-Teh Lee
• Format: Others
• Language: en_US
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/41357446507197551068

碩士 === 大同大學 === 資訊工程學系(所) === 94 === In the real-time system, the system usually supports the application that includes the task set with hard and soft real-time tasks. The traditional researches on the task scheduling in real-time operating systems were setting the priority for providing service to soft tasks after that can promise meet deadline of hard tasks. Therefore, those scheduling schemes were trying to provide better average meet ratio for soft tasks. But that have no considerate to the deadline of each task. In this thesis, an adaptive multi-level scheduler is proposed. The proposed architecture applies a tuner, called importance tuner, to evaluate the importance of each task, including hard tasks and soft tasks, and increase or decrease the weight of importance the task. Then the task is being assigned to the multiple EDF schedulers by its importance weight. In addition to the multi-level EDF scheduler, we are also building up a second level RM scheduler to schedule first level EDF schedulers as the normal tasks. The proposed adaptive multi-level scheduler considers the operating environment of the real-time operation system the real world. Based on μC/OS-II, we have implemented the proposed scheduling architecture that can improve the system performance and fit for almost all real-time applications.