Modified IUF Scheduling Algorithm for Real Time Systems

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 trade-off of the quality of computations in favor of meeting the deadline constraints. This paper proposes an algorithm which is basically a planning based offline scheduling algorithm. In this model, a task is logically decomposed into two subtasks, mandatory and optional. The mandatory portion of each task is scheduled using instantaneous utilization and optional portion is scheduled using shortest job first. It is observed that scheduling performance metrics such as schedulability, CPU utilization, context switching, response time and reliability are improved as compared to scheduling algorithms such as RM, EDF, LLF, MUF, IUF and IRIS scheduling algorithms.