A dynamic priority assignment strategy for real-time task

Most of the real-time task scheduling algorithms assign the priorities of tasks according to their three attributes, deadlines, slack times and value(density), but seldom synthetically analyze the effects of the three factors on the priorities of tasks. This paper studies the dynamic value density and urgency of a task by studying its three attributes, and based on which, a dynamic priority assignment strategy, DPA, is proposed. In this strategy, two parameters p and q are used to adjust the weight that the value density and urgency of a task impact on its priority. Finally, the result of simulations shows that a scheduler using DPA strategy could improve the gained-value of the system, reduce the deadline miss ratio.