PPT Slide
Scheduling Problems
- The table on page 288 gives four jobs and their CPU time, arrival time and priority.
- Figure 8.8 shows the job scheduling for four algorithms (FCFS, SJF, Priority, RR w/ quantum=2 and RR with continuous zero-time context switches)
- Note SJF gives best average job turnaround.
- FCFS is horrible, but subject to “convoy effect” (large processes up front create large waits).
- The first RR I respectfully disagree with -- it’s RR with SJF selection (note how Job 2 runs first, Job 4 second, etc.)!
- The RRs, though, aren’t the best or worst, but give fair response time.