CPU scheduling

1. CPU Scheduling in Operating
Systems
Presented by: [Your Name]

2. Learning Objectives
• Understand the need for CPU scheduling.
• Learn various CPU scheduling algorithms.
• Compare scheduling strategies.
• Analyze advantages and drawbacks of each.

3. What is CPU Scheduling?
• The OS decides which of the ready processes
should be assigned to the CPU.
• Improves CPU utilization and responsiveness.
• Essential in multiprogramming environments.

4. Scheduling Criteria
• CPU Utilization
• Throughput
• Turnaround Time
• Waiting Time
• Response Time
• Fairness

5. Scheduling Types
• Preemptive: CPU can be taken from a process.
• Non-preemptive: Process keeps CPU until it
terminates or waits.

6. First-Come, First-Served (FCFS)
• Non-preemptive.
• Processes are served in order of arrival.
• Drawback: Can lead to Convoy Effect.

7. Shortest Job First (SJF)
• Can be preemptive or non-preemptive.
• Shortest burst time first.
• Pros: Optimal in average waiting time.
• Cons: Requires knowledge of burst time.

8. Round Robin (RR)
• Preemptive scheduling.
• Each process gets CPU for a fixed time
quantum.
• Used in time-sharing systems.

9. Priority Scheduling
• Each process assigned a priority.
• CPU given to the highest priority process.
• Issue: Starvation of low-priority processes.
• Solution: Aging.

10. Comparison Table
Algorithm Preemptive Avg Waiting Time Use Case
FCFS No High Simple systems
SJF Yes/No Low Batch jobs
RR Yes Moderate Interactive
Priority Yes/No Varies Mixed priority
systems

11. Real-world Example
• Multitasking in smartphones uses Round
Robin and Priority scheduling.
• Batch systems may use FCFS or SJF.

12. Interactive Question
• Q: Which scheduling algorithm would you use
in a real-time system and why?

13. Summary
• CPU scheduling ensures efficient CPU usage.
• Different algorithms suit different
environments.
• Knowing trade-offs is key to system design.

14. Thank You
• Contact Info: [email / phone if applicable]