Instantaneous Utilization Based Scheduling Algorithms for Real Time Systems

This paper proposes a new novel scheduling algorithms to schedule periodic tasks for soft real time system. This is a planning based offline scheduler where tasks are scheduled on the basis of its instantaneous utilization. Here after every quantum of execution, instantaneous utilization of each task is calculated. Task which is having highest instantaneous utilization is scheduled to the processor. Since Instantaneous utilization factor(IUF) is temporarily variant factor, the priority of each task will vary continuously. Also It is often more desirable to complete some portions of every task rather than giving up completely the processing of some tasks. The Imprecise Computation Model was introduced to allow for the tradeoff of the quality of computations in favor of meeting the deadline constraints. It is observed that scheduling performance metrics such as schedulability, CPU utilization, context switching, response time and reliability are improved by this approach as compared to scheduling algorithms such as RM, EDF, LLF, MUF scheduling algorithms.