Modified RR Algorithm with Dynamic Time Quantum for Externally Prioritized Tasks

Abstract

Abstract-The objective of this paper is to modify Round Robin scheduling for soft real time systems. It introduces a variation of round robin algorithm which can schedule tasks considering their priorities in a round robin fashion. Simple Round Robin scheduling algorithm and Priority scheduling algorithm, both have their own drawbacks. The proposed algorithm removes the drawbacks of Round Robin scheduling and Priority scheduling. The proposed scheduling algorithm calculates different time slices for individual processes considering their priorities. Experimental analysis reveals that the proposed algorithm produces better average turnaround time, average waiting time and less number of context switches than some existing algorithms useful for interactive systems.

A new RR Scheduling Approach for Real Time Systems using Fuzzy Logic

“…From the above comparisons, it is observed that the proposed algorithm is performing better than the algorithm PBDRR proposed in paper [7] and DQT proposed in paper [9] in terms of average waiting time, average turnaround time and number of context switches. If the CPU burst times of the processes vary very widely the algorithm doesn't produce good result.…”

“…In [8] the authors have made the priority and time slice for a process dynamic by calculating the weighted mean values of time quantum and priorities of the processes and considering the burst time of the processes. The algorithm introduced in [9] calculates the time slice of each process in each round dynamically considering the priority of a process and the average and shortest burst time of all the currently running processes. Fuzzy logic is applied in the design and implementation of a rule-based scheduling algorithm to solve the shortcoming of well-known scheduling algorithms in [10].…”

“…To compare the performance of the algorithm with the algorithms introduced in [7] (PBDRR), [9] (DTQ), three cases of the data set are considered: the processes with burst time in increasing, decreasing and random order respectively.…”

Improving Round Robin Process Scheduling Algorithm

“…The objective of [3] is to modify Round Robin algorithm by adjusting time slices of different rounds depending on the remaining CPU bursts of currently running processes and coinciding their waiting time until that round in request of the other processes' waiting time. The [4] proposal calculates different time slices for individual processes coinciding their priorities. The primary objective of [5] is to optimize system performance according to the criteria deemed most important by system designers.…”

“…Some other process scheduling algorithms include First Come First Serve (FCFS) and Shortest Job First (SJF) algorithms [7], [8]. FCFS algorithm executes the first process that comes in the ready queue and that process is executed fully till its burst time is finished [4], [6], [8]. Shortest Job First (SJF) algorithm executes the process with the minimum burst time first and executes it till its burst time is finished.…”