Round-robin scheduling

Serve the front of a FIFO queue of runnable tasks for at most one scheduling quantum. If the task finishes or must wait for input-output, it leaves the CPU earlier; if it remains runnable after consuming its allowance, append it to the rear of the ready queue. In the example under process scheduling, the ready queue at time 2 is B, C, A: B arrived at time 1, C joins at the boundary, then A is requeued. That one convention determines the subsequent order.

The maximum amount of CPU execution allotted in one turn by round-robin scheduling. A task can finish before consuming its scheduling quantum. When other tasks remain runnable, a shorter scheduling quantum provides more frequent turns at the cost of more frequent context switches.