Process Arrival Time CPU Burst I/O Burst Total CPU Time A 0 5 4 11 B 2 1 3 5 C 6 6 2 14 D 8 2 1 9 Assuming a single processor, create a scheduling simulation for a two-level feedback queue where the top-level queue is managed as Shortest Job First (with Preemption) and the bottom-level is managed as Shortest Job First (without Preemption). When a process is preempted from the top-level queue, it will be demoted to the bottom-level queue. Higher-level queue processes will preempt lower-level queue processes (even though the bottom level runs without preemption when executing all jobs scheduled on its level, a process arriving in the top-level queue will preempt any process running on the bottom-level queue). There is an aging mechanism that promotes a process to the top-level queue level if it has waited in the bottom-level queue for 4 consecutive time units. For this simulation, there will be two ready queues (one at each level). When processes arrive in the ready queue at the same level and at the same time, priority will always be determined by CPU burst time. Shortest job first: Process Thread Arrival Time CPU Burst I/O Burst Total CPU Time A A1 0 5 4 11 B B1 2 1 3 5 C C1 6 6 2 14 D D1 8 2 1 9
|
Process |
Arrival Time |
CPU Burst |
I/O Burst |
Total CPU Time |
|
A |
0 |
5 |
4 |
11 |
|
B |
2 |
1 |
3 |
5 |
|
C |
6 |
6 |
2 |
14 |
|
D |
8 |
2 |
1 |
9 |
Assuming a single processor, create a scheduling simulation for a two-level feedback queue where the top-level queue is managed as Shortest Job First (with Preemption) and the bottom-level is managed as Shortest Job First (without Preemption). When a process is preempted from the top-level queue, it will be demoted to the bottom-level queue. Higher-level queue processes will preempt lower-level queue processes (even though the bottom level runs without preemption when executing all jobs scheduled on its level, a process arriving in the top-level queue will preempt any process running on the bottom-level queue). There is an aging
For this simulation, there will be two ready queues (one at each level). When processes arrive in the ready queue at the same level and at the same time, priority will always be determined by CPU burst time.
Shortest job first:
|
Process |
Thread |
Arrival Time |
CPU Burst |
I/O Burst |
Total CPU Time |
|
A |
A1 |
0 |
5 |
4 |
11 |
|
B |
B1 |
2 |
1 |
3 |
5 |
|
C |
C1 |
6 |
6 |
2 |
14 |
|
D |
D1 |
8 |
2 |
1 |
9 |
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