Round_Robin_Scheduling

1. Round Robin Scheduling
• A CPU Scheduling Algorithm
• Prepared Presentation

2. Introduction
• • Round Robin is a preemptive CPU scheduling
algorithm.
• • Each process gets an equal fixed time called
Time Quantum.
• • Ideal for time-sharing and multi-user
operating systems.

3. Definition
• • Each process receives CPU time in cyclic
order.
• • A process is preempted when its time
quantum expires.
• • Ensures fairness and avoids starvation.

4. How Round Robin Works
• 1. All processes are placed in a ready queue.
• 2. CPU executes each process for a fixed time
quantum.
• 3. If process is not finished, it is moved to
queue end.
• 4. Repeat cycle until all processes complete.

5. Key Concept: Time Quantum
• • If quantum is too small → Many context
switches → Overhead increases.
• • If quantum is too large → RR behaves like
FCFS.
• • Must be chosen carefully for balanced
performance.

6. Example (Gantt Chart Concept)
• Processes: P1=5, P2=3, P3=1
• Quantum = 2
• Execution Order:
• P1 → P2 → P3 → P1 → P2 → P1

7. Advantages
• • Fair to all processes.
• • No starvation.
• • Low response time.
• • Ideal for interactive and time-sharing
systems.

8. Disadvantages
• • High overhead due to frequent context
switching.
• • High turnaround time.
• • Performance depends heavily on time
quantum.
• • Not optimal for CPU-bound tasks.

9. Applications
• • Time-sharing operating systems.
• • Interactive systems and user interfaces.
• • Network routers and packet scheduling.

10. Conclusion
• • Round Robin ensures fairness and
responsiveness.
• • Widely used in multitasking operating
systems.
• • Efficiency depends on selecting an
appropriate time quantum.