The Design, Implementation and Evaluation of SMART: A Scheduler for Multimedia Applications

Jason Nieh, Monica S. Lam

Proceedings of the 16th ACM Symposium on Operating Systems Principles, Saint-Malo, France, October 5-8, 1997, pp. 184-197. (Also available i)


Real-time applications such as multimedia audio and video are increasingly populating the workstation desktop. To support the exe- cution of these applications in conjunction with traditional non-real- time applications, we have created SMART, a Scheduler for Multi- media And Real-Time applications. SMART supports applications with time constraints, and provides dynamic feedback to applica- tions to allow them to adapt to the current load. In addition, the sup- port 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 pro- cessor is to be shared among applications of the same priority. As the system load changes, SMART adjusts the allocation of resources dynamically and seamlessly. SMART is unique in its ability to automatically shed real-time tasks and regulate their exe- cution rates 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 sys- tem and measured its performance against other schedulers in exe- cuting real-time, interactive, and batch applications. Our results demonstrate SMART’s superior performance in supporting multi- media applications.



Columbia University Department of Computer Science