Improved Multilevel Feedback Queue Scheduling Using Dynamic Time Quantum and Its Performance Analysis

Multilevel feedback queue scheduling algorithm allows a process which is entering to the system to move between several queues. Here, the processes initially does not come with any priority but during scheduling the processes according to their CPU burst time may be shifted to the lower level queues. Here an effective dynamic time slice is used to schedule the processes. As a result we found reduction in turnaround time, average waiting time and better throughput as compared to the previous approaches and hence increase in the overall performance. A control flow diagram is used to describe the sequence of flow of control of the processes with different conditional statements, repetition of the flow structures and case conditions. The algorithm is proposed in such a way that it reduces the starvation of the long processes. An entering process is inserted into the top level queue. When selected, processes in the queue are allocated a relatively small time slice. Upon expiration of time slice the process is moved to lower level queue. Keywords— CPU burst time, turnaround time,waiting time,throughputs, dynamic time quantum,shifting to lower queues, RR scheduling algorithm.