Multilevel feedback queue scheduling allows a process to move between queues.
Separate processes into categories based on their need for the processor. Give preference to I/O bound processes. This scheduling algorithm is intended to meet the following design requirements for multi-mode systems: So tasks are dispatched according to the execution characteristics. For each level a different or maybe same time quanta is set which is at last followed by FCFS. Therefore, each process takes 5.2ms to execute.Considering feedback queue as multilevel feedback queue, we can go ahead. Therefore, Average Waiting Time = (3 + 13 + 25 + 0 + 9) / 5 = 10msįirst finding Turnaround Time of each process. Priority Scheduling Example with Gantt Chartįirst of all, we have to find out the waiting time of each process. Therefore, each process takes 4ms to execute. Therefore, Average Turnaround Time = (3 + 13 + 4 + 14 + 2) / 5 = 7.2ms Therefore, Average Waiting Time = (0 + 7 + 0 + 9 + 0) / 5 = 3.2msįirst of all, we have to find the turnaround time of each process. Therefore, Average Turnaround Time = (44 + 21 + 24) / 3 = 29.66msįirst of all, we have to find the waiting time for each process. Same concept for finding the Turnaround Time. Therefore, Average Waiting Time = (14 + 15 + 16) / 3 = 15ms Time Quantum is 5ms.įor finding Average Waiting Time, we have to find out the waiting time of each process. Here is the Round Robin scheduling example with gantt chart. Therefore, Throughput will be same as above problem i.e., 11.6ms for each process. Now, Average Waiting Time = (3 + 34 + 18 + 8 + 0) / 5 = 12.6msĪccording to the SJF Gantt chart and the turnaround time formulae, Here arrival time is common to all processes(i.e., zero). We will apply the same formula to find average waiting time in this problem. It means one process executes in every 11.6 ms. Process P1, P2, P3, P4, and P5 takes 5ms, 24ms, 16ms, 10ms, and 3ms to execute respectively. Total Turnaround Time = (5 + 29 + 45 + 55 + 58)ms = 192msĪverage Turnaround Time = (Total Turnaround Time / Total Number of Process) = (192 / 5)ms = 38.4ms Turnaround Time = Waiting time in the ready queue + executing time + waiting time in waiting-queue for I/O 
Therefore, average waiting time = (0 + 5 + 29 + 45 + 55) / 5 = 25 ms Waiting Time = Starting Time - Arrival TimeĪverage Waiting Time = Waiting Time of all Processes / Total Number of Process Now we calculate the average waiting time, average turnaround time and throughput.Īverage Waiting Time and Turnaround Time Average Waiting Timeįirst of all, we have to calculate the waiting time of each process.
The length of the CPU burst time given in millisecond. Let's see.Ĭonsider the above set of processes that arrive at time zero. We will see here that how CPU scheduler uses scheduling algorithms during execution of process. Today we will practice problems on different types of CPU Scheduling Algorithms.
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