Evaluating Dynamic Failure Probability for Streams with (m,k)-Firm Deadlines

In [5], we introduced the notion of (m; k)-firm deadlines to better express the timing requirements of real-time streams. For a stream with (m; k)-firm deadlines, the quality of service is acceptable as long as at least m customers meet their deadlines in any window of k consecutive customers. If fewer than m customers meet their deadlines in a window of k consecutive customers, the stream is said to have encountered a dynamic failure. Based on this model, we proposed a priority-based service policy for scheduling multiple real-time streams on a single resource. This scheme was compared to a single priority scheme where all customers are serviced at the same priority level. Simulation results show that the proposed distance-based priority scheme reduces the probability of dynamic failure. In this paper, we develop an analytic model for both the single priority scheme and the distancebased priority scheme. This model is used to compute the probability of dynamic failure of a real-time..