Example of Multilevel Feedback Queue

• Three queues:

1. Q0 – time quantum 8 milliseconds
2. Q1 – time quantum 16 milliseconds
3. Q2 – FCFS

• Scheduling

1. A new job enters queue Q0 which is served FCFS. When it gains CPU, job receives 8 milliseconds.  If it does not finish in 8 milliseconds, job is moved to queue Q1.
2. At Q1 job is again served FCFS and receives 16 additional milliseconds.  If it still does not complete, it is preempted and moved to queue Q2.