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Process Scheduling II ( 5.3). CPE 261403 - Operating Systems http://www.e-cpe.org/moodle. Scheduling Criteria (5.2). CPU Utilization Throughput Turnaround time Waiting time Response time. Scheduling Algorithms (5.3). FCFS SJF (non-preemptive / preemptive) Priority Scheduling
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Process Scheduling II(5.3) CPE 261403 - Operating Systems http://www.e-cpe.org/moodle
Scheduling Criteria (5.2) • CPU Utilization • Throughput • Turnaround time • Waiting time • Response time
Scheduling Algorithms (5.3) • FCFS • SJF (non-preemptive / preemptive) • Priority Scheduling • Round-Robin Scheduling • Multilevel Queue Scheduling • Multilevel Feedback-Queue Scheduling
Priority Scheduling • Defining Priorities • Internally Defined Priorities • External priorities
IBM 7094 at MIT When closing down in 1973, found a process submitted in 1967 (Myth)
Round Robin Scheduling • Preemptive by Nature • Defines a Time Quantum • Time Quantum >> Context Switch Time
Multilevel Queue Scheduling • Scheduling within & among queues • Use simple priority or CPU time slice (quota)
Multilevel Feedback Queue • Example: Q1=RR, Q2=RR, Q3=FCFS
Multilevel Feedback Queue • Parameters: • Number of queues • Scheduling algorithms for each queue • When to upgrade a process • When to downgrade a process • Which queue should a new process enter