Round Robin Scheduling

Round Robin (RR) is a preemptive CPU scheduling algorithm designed for time-sharing systems where each process is assigned a fixed time unit called a time quantum or time slice. Processes are kept in a circular queue, and the CPU scheduler goes around this queue, allocating the CPU to each process for the time quantum. If a process's CPU burst time is less than the time quantum, it will release the CPU voluntarily upon completion. If the burst time is longer, the process is preempted after the time quantum expires and placed at the tail of the ready queue. The key advantage of Round Robin is its fairness - each process gets an equal share of CPU time. It provides good response time for interactive systems and prevents starvation. The performance of RR depends heavily on the size of the time quantum: too large a quantum degenerates to FCFS, while too small a quantum increases context switching overhead reducing CPU utilization. RR is particularly effective when process burst times vary widely or when the system needs to provide responsive interactive performance. Modern operating systems often use RR as the default scheduling algorithm for interactive processes, sometimes with dynamic time quantum adjustment based on system load and process priorities.