The BEST scheduler for integrated processing of best-effort and soft real-time processes

Algorithms for allocating CPU bandwidth to soft real-time processes exist, yet best-effort scheduling remains an attractive model for both application developers and users. Best-effort scheduling is easy to use, provides a reasonable trade-off between fairness and responsiveness, and imposes no extra overhead for specifying resource demands. However, best-effort schedulers provide no resource guarantees, limiting their ability to support processes with timeliness constraints. Reacting to the need for better support of soft real-time multimedia applications while recognizing that the best-effort model permeates desktop computing for very good reasons, we have developed BEST, an enhanced best-effort scheduler that combines desirable aspects of both types of computing. BEST provides the well-behaved default characteristics of best-effort schedulers while significantly improving support for periodic soft real-time processes. BEST schedules using estimated deadlines based on the dynamically detected periods of processes exhibiting periodic behavior, and assigns pseudo-periods to nonperiodic processes to allow for good response time. This paper discusses the BEST scheduling model and our implementation in Linux and presents results demonstrating that BEST outperforms the Linux scheduler in handling soft real-time processes, outperforms real-time schedulers in handling best-effort processes, and sometimes outperforms both, especially in situations of processor overload

Use of Adjunct Faculty Members in Classroom Teaching in Departments of Pharmacy Practice

Objective. To determine trends among departments of pharmacy practice regarding use of adjunct faculty members for classroom-based teaching and to assess departmental support provided to these faculty members

Toward a Taxonomy of Time-Constrained Applications

We are developing a taxonomy for classifying applications based on their time constraints. The taxonomy is based on three components that capture the key characteristics between different classes of applications: the process's execution behavior, its timing constraints, and the level of guarantee it is willing to accept from the system. The taxonomy is useful for two reasons: it provides a survey of the types of existing applications, and it is a tool for understanding how to develop integrated schedulers that handle multiple classes of applications simultaneously