CPU Non-Preemptive Scheduling

1. CPU Non-Preemptive
Scheduling

2. Member
 Mahmudullah 151-15-5073
 M. Munem Mostaqem 151-15-4873
 Md. Fardin Hassan 152-15-5532
 Mehedi Hasan Ratul 152-15-5711
 Md Jahid Hasan 152-15-5787
 Mohammad Shakhawat Hossain 151-15-4727

3. Definition
• Preemptive Scheduling.
- SRTF, Priority, Round Robin, etc.
 Non-preemptive Scheduling.
-FCFS, SJF, Priority, etc.

4. FCFS
Process:
 Non-preemptive scheduling algorithm.
 Follow first in first out (FIFO) method.

5. FCFS
Example 1: (Without Arrival time)

6. FCFS
TotalWaitTime=
AverageWaitingTime =
TotalTurn AroundTime=
AverageTurn Around time =

7. FCFS
Example 2: ( with ArrivalTime)

8. FCFS
TotalWaitTime=
AverageWaitingTime =
TotalTurn AroundTime=
AverageTurn Around time =

9. SJF
Process:
 once CPU given to the process it cannot be preempted until
completes its CPU burst
 Ready queue is treated as a priority queue based on smallest CPU
time requirement.

10. SJF
Example 1: (Without arrival time)

11. SJF
TotalWaitTime
6 + 0 + 3 = 9 ms
AverageWaitingTime = (TotalWaitTime) / (Total number of
processes)
9/3 = 3 ms
TotalTurn AroundTime
30 + 3 + 6 = 39 ms
AverageTurn Around time = (TotalTurn AroundTime) / (Total
number of processes)
39 / 3 = 13 ms

12. SJF
Example 2: (With ArrivalTime)

13. SJF
TotalWaitTime= 0 + 7 + 15 + 9 = 31 ms
AverageWaitingTime = 31/4 = 7.75 ms
TotalTurn AroundTime = 8+11+ 14+24= 57
AverageTurn Around time = 57/4 = 14.25 ms

14. Priority
Process:
 Each process is assigned a priority. Process with highest priority is
to be executed first and so on.
 Processes with same priority are executed on first come first
served basis.

15. Priority
Example: (With Arrival time)
Gantt chart

16. Priority
Average Wait Time : (9+5+12+0) / 4 = 6.5

17. Priority
Gantt chart:
Example 2: (without Arrival time)

18. Priority

19. Question?

20. THANKYOU!