Research And Improvement In Task Schedule Of The Enbedded Real-Time Operating System

To fulfil the real-time requirements of the tasks is the most important characteristic of the real-time scheduling. There is often much more attention paid on the real-time characteristic, but the correctness is always not concerned enough. The relation between the two characteristics is very close.Considering the embedded system's characteristics, attending the real-time and correct requirements, taking the idea of the share-dirven scheduling, a two layers task scheduling frame is proposed. Task scheduling is not just a policy, and needs the supply to make sure the performing of the policy. This frame can also reduce the work for improve or change the task scheduling.There are few standards for the comparing of the real-time task schedules. A given circumstance real-time limit idea is presented. This idea can give a criterion to analyze the characteristics of the different task schedules. The idea can also use to help calculating the consumption of the task scheduling itself, and expand the use of the schedulability test.By researching the mechanism of the uC/OS-II's task scheduling kernel, the round-robin policy and the polling server policy is appended. The polling server policy can distribute the CPU resources dynamically. This task scheduling can be a kind of share-dirven scheduling, and an instance of the two layers task scheduling frame.