A SMART Scheduler for Multimedia Applications

摘要

Real-time applications such as multimedia audio and video are increasingly populating the workstation desktop. To support the execution of these applications in conjunction with traditional non-real-time applications, we have created SMART, a Scheduler for Multimedia And Real-Time applications. SMART supports applications with time constraints, and provides dynamic feedback to applications to allow them to adapt to the current load. In addition, the support for real-time applications is integrated with the support for conventional computations. This allows the user to prioritize across real-time and conventional computations, and dictate how the processor is to be shared among applications of the same priority. As the system load changes, SMART adjusts the allocation of resources dynamically and seamlessly. It can dynamically shed real-time computations and regulate the execution rates of real-time tasks when the system is overloaded, while providing better value in underloaded conditions than previously proposed schemes. We have implemented SMART in the Solaris UNIX operating system and measured its performance against other schedulers commonly used in research and practice in executing real-time, interactive, and batch applications. Our experimental results demonstrate SMART'S superior performance over fair queueing and UNIX SVR4 schedulers in supporting multimedia applications.