Question 1 : find the average Turn Around Time and Waiting Time of
following processes using MLFQS(MULTILEVEL FEEDBACK QUEUE SCHDULING)
process scheduling algorithm? Consider the following processes with
their Arrival Time, Burst Time. Question criteria :
(1) There are four queue Q1, Q2, Q3, Q4
(2) Queue with their time stamp Q1(T.S=4), Q2(T.S=8), Q3(T.S=16),
Q4(FCFS)
(in Q1, Q2, Q3, we use Round Robin and in Q4 we use FCFS scheduling
algorithms)
| Process | Arrival Time | Burst Time |
|---|---|---|
| P1 | 1 | 6 |
| P2 | 4 | 8 |
| P3 | 5 | 12 |
| P4 | 8 | 14 |
| P5 | 12 | 6 |
| P6 | 10 | 10 |
| P7 | 8 | 8 |
| P8 | 16 | 6 |
Formula:
Turnaround Time (TAT) = Completion Time - Arrival Time
Waiting Time (WT) = Turnaround Time - Burst Time
Solution:
Gantt Chart
| P1 (1-5) | P2 (5-9) | P3 (9-13) | P4 (13-17) | P7 (17-21) | P6 (21-25) | P5 (25-29) | P8 (29-33) | P1 (33-35) | P2(35-39) | P3(39-47) | P4(47-55) | P7(55-59) | P6(59-65) | P5(65-67) | P8(67-69) | P4(69-71)
Calculations:
| Process | Completion Time | Turnaround Time (TAT) | Waiting Time (WT) |
|---|---|---|---|
| P1 | 35 | 34 | 28 |
| P2 | 39 | 35 | 27 |
| P3 | 47 | 42 | 30 |
| P4 | 71 | 63 | 49 |
| P5 | 67 | 55 | 49 |
| P6 | 65 | 55 | 45 |
| P7 | 59 | 51 | 43 |
| P8 | 69 | 53 | 47 |
Average Turnaround Time:
(34 + 35 + 42 + 63 + 55 + 55 + 51 + 53) / 8 = 48.5
Average Waiting Time:
(28 + 27 + 30 + 49 + 49 + 45 + 43 + 47) / 8 = 39.75
Question 2 : find the average Turn Around Time and Waiting Time of
following processes using MLFQS(MULTILEVEL FEEDBACK QUEUE SCHDULING)
process scheduling algorithm? Consider the following processes with
their Arrival Time, Burst Time. Question criteria :
(1) There are four queue Q1, Q2, Q3, Q4
(2) Queue with their time stamp Q1(T.S=2), Q2(T.S=4), Q3(T.S=8),
Q4(FCFS)
(in Q1, Q2, Q3, we use Round Robin and in Q4 we use FCFS scheduling
algorithms)
| Process | Arrival Time | Burst Time |
|---|---|---|
| P1 | 0 | 6 |
| P2 | 5.0 | 2 |
| P3 | 8.0 | 5 |
| P4 | 10 | 8 |
| P5 | 14 | 4 |
| P6 | 18 | 3 |
| P7 | 22 | 2 |
| P8 | 24 | 10 |
Formula:
Turnaround Time (TAT) = Completion Time - Arrival Time
Waiting Time (WT) = Turnaround Time - Burst Time
Solution:
Gantt Chart
| P1 (0-5) | P2 (5-7) | P1 (7-8) | P3 (8-10) | P4 (10-12) | P3 (12-14) | P5 (14-16) | P4 (16-18) | P6 (18-20) | P3(20-21) | P5(21-22) | P7(22-24) | P8(24-26) | P4(26-28) | P6(28-29) | P5(29-30) | P8(30-34) | P4(34-36) | P8(36-40)
Calculations:
| Process | Completion Time | Turnaround Time (TAT) | Waiting Time (WT) |
|---|---|---|---|
| P1 | 8 | 8 | 2 |
| P2 | 7 | 2 | 0 |
| P3 | 21 | 13 | 8 |
| P4 | 36 | 26 | 18 |
| P5 | 30 | 16 | 12 |
| P6 | 29 | 11 | 8 |
| P7 | 24 | 2 | 0 |
| P8 | 40 | 16 | 6 |
Average Turnaround Time:
(8 + 2 + 13 + 26 + 16 + 11 + 2 + 16) / 8 = 11.75
Average Waiting Time:
(2 + 0 + 8 + 18 + 12 + 8 + 0 + 6) / 8 = 6.75