Improving Dual Priority scheduling algorithm by implementing various low priority orders

Dual Priority scheduling is a variation of the Fixed Priority scheduling paradigm inreal-time systems. It was introduced to make non-real-time jobs complete soonerwhile ensuring that real-time jobs still meet their deadlines. In Fixed Priorityscheduling, each task is assigned with a fixed priority and the task executes in thatpriority throughout the schedule. In Dual Priority algorithm every task has twopriorities, high and low each task runs in low priority as soon as it arrives and con-tinues executing in its low priority order until it reaches its priority promotion time,and executes at its high priority level until completion. In original Dual Priorityscheduling algorithm the low and high priority orderings are the same. This thesisfocuses on implementing various low priority orderings to examine which low priorityordering should be chosen to make more tasks schedulable. We found that in manycases, having the low priority order be the reverse of the high priority order allowsmore task sets to be schedulable. Task sets whose low priority is ordered accordingto decreasing laxity (the time a job can remain in wait queue without missing adeadline) also seemed to be schedulable more often than other options.