Round Robin

• Each process gets a CPU time quantum, usually 10-100 milliseconds. After that, it is preempted and added to the end of the ready queue.

• If there are n processes in the ready queue and the time quantum is q then each process gets 1/n of the CPU time in chunks of at most q units at once. No process waits more that (n-1)q time units to be scheduled.

• Performance:

.

• Large q => FCFS.
• Small q => Context switch overhead!

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