基于QoS控制的连续媒体服务任务调度

连续媒体服务如视频，音频等是一类新的实时应用，要求在一统一的操作系统框架内支持强，弱实时应用，而传统的操作系统中的调度策略不能很好的支持该类应用。文中提出了一种新的ＱｏＳ描述方法，并在此基础上提出支持连续媒体流的，基于ＱｏＳ的启发式任务调度算法。该算法考虑了多媒体任务的成功率和连续失败数在资源有限的前提下，尽量保证所有媒体流的服务质量。

TASK SCHEDULING BASED ON QoS CONTROL FOR CONTINUOUS MEDIA SERVICES

Continuous media service is a new kind of real time applications. It requires that hard and soft real time tasks should be supported in an integrated operating system framework. But the scheduling policies in traditional OS(e.g., UNIX or Windows NT)can't support this application to the best. This paper proposes a new QoS method, based on which a QoS based heuristic task scheduling algorithm supporting continuous media streams is described. The algorithm takes into account the success ratio and consecutive fail count of multimedia tasks in order to guarantee the quality of all media streams. Finally, simulation and comparison are performed to validate the effectiveness of this algorithm.