The document discusses CPU scheduling, particularly focusing on the round-robin algorithm, which is a preemptive scheduling method that allows each process to use the CPU for a fixed amount of time in a cyclic manner. It highlights how the round-robin algorithm operates by comparing process burst times to a designated time quantum and offers examples of problem-solving using Gantt charts and calculations for CPU efficiency and turnaround times. Additionally, a sample case with processes and their respective times is presented for clarification.

1. CPU Scheduling
Round Robin
Armen Bacuteng Ryan Czar Rayray Joshua Roman Reyes Ralph Gylan Asistin
Gwen Bustamante Anne Kylie Binong

2. INTRODUCTION
• Schedule shows the methods in order assigned to operate on available
central processing unit (CPU). Fixed CPU timing Methods or
algorithms have been developed. The main objective of these
algorithms is. For maximum CPU usage, Average Waiting Time
(AWT), Average turnaround time (ATAT), NCS, increase throughput
and do their best to be fair to everyone. Some examples of CPU
Scheduling are First Come First Serve (FCFS), Preemptive Shortest
Job First (PSJF), Round Robin (RR) which are valuable assets of CPU
Scheduling.

3. ROUND ROBIN
• The Round-robin scheduling algorithm is a kind of preemptive First come, First Serve CPU
Scheduling algorithm where each process in the ready state gets the CPU for a fixed time in a
cyclic way (turn by turn). It is the oldest scheduling algorithm, which is mainly used
for multitasking.
• The Round robin scheduling algorithm is one of the CPU scheduling algorithms in which
every process gets a fixed amount of time quantum This processing is done in FIFO order which
suggests that processes are executed on a first-come, first-serve basis.

4. ROUND ROBIN
• Computing the round robin is a clock -driven process, all the processes are added to the
ready queue. First, the burst time of every process is compared to the time quantum of the CPU.
If the burst time of the process is less than or equal to the time quantum in the round-robin
scheduling algorithm, the process is executed to its burst time. If the burst time of the process is
greater than the time quantum, the process is executed up to the time quantum (TQ). When the
time quantum expires, it checks if the process is executed completely or not.

5. HOW TO SOLVE ROUND ROBIN?
• After knowing the time quantum, burst time and arrival time of a certain processes,
solve the following:
• Gantt Chart
• CPU Efficiency
𝑇𝐵𝑇
𝑇𝐹𝑇
x 100
• Throughput
# 𝑜𝑓 𝐽𝑜𝑏𝑠
𝑇𝐹𝑇
• Average Waiting Time = Response Time – Arrival Time
• Average Turn Around Time = Finish Time – Arrival Time
TBT = Total Burst Time
TFT = Total Finish
Time

6. Let’s try this! Time Quantum - 2
Process Burst Time Arrival Time
P1 1 4
P2 0 6
P3 2 2
P4 3 4
P5 4 2

7. Let’s try this!
• Time Quantum - 2
Process Burst Time Arrival Time
P1 1 4
P2 0 6
P3 2 2
P4 3 4
P5 4 2

8. Let’s try this!
Time Quantum - 4

9. TOOL USED
• NETBEANS