Research On Policy And Algorithm Of Task Scheduling In Real-time System

With the widely applications of Real-time system, studies on Real-time system are attached more and more attentions. Real-time task scheduling is the critical issue of Real-time system, so researches on it are more and more significant. This article commences on deficiencies of current researches about Real-time task scheduling, and then supplements and advances some methods.It is more and more common that all kinds of Real-time tasks exist in a system. And it is necessary to build up a compositive scheduling framework, which supports various types of Real-time tasks. So the paper makes progress according to shortages existing in current references. At present, only one attribute of tasks is considered as the scheduling basis in most of algorithms, and multi-characters of tasks, resources and events, which may influence task scheduling, are rarely taken into consideration at the same time. So on the basis of compositive scheduling framework presented above, a new scheduling algorithm is put forward, which considers multi-characters of task, resources and events synthetically.Considering the similarity of Workflow scheduling and that of Real-time system, it is available to apply Workflow scheduling to that of soft Real-time tasks with precedence constraints. Therefore, a scheduling model of soft Real-time tasks with precedence constraints, based on Workflow, is proposed here. Specially, a deep study on and/or precedence constraint tasks is made at the end of the paper.