Lecture20nFull - COT 4600 Operating Systems Spring 2011...

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Click to edit Master subtitle style 8/1/11 Lecture 20 COT 4600 Operating Systems Spring 2011 Dan C. Marinescu Office: HEC 304 Office hours: Tu-Th 5:00-6:00 PM
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Lecture 20 8/1/11 Lecture 20 - Tuesday April 5, 2011 n Last time: ¨ Tread coordination with a bounded buffer n Today: ¨ Scheduling ¨ Multi-level memories ¨ Memory characterization ¨ Multilevel memories management using virtual memory ¨ Adding multi-level memory management to virtual memory n Next Time: ¨ Page replacement algorithms 22
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Lecture 20 8/1/11 Scheduling n Basic concepts; scheduling objectives. n Scheduling policies ¨ First-Come First-Serve (FCFS) ¨ Shortest Job First (SJF) ¨ Round Robin (RR) ¨ Preemptive/non-preemptive scheduling ¨ Priority scheduling n Priority inversion n Schedulers ¨ CPU burst. Estimation of the CPU burst ¨ Multi-level queues ¨ Multi-level queues with feedback ¨ Example: the UNIX scheduler 33
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Lecture 20 8/1/11 Scheduling – basic concepts n Scheduling + assigning jobs to machines. n n Scheduling in the general case in a NP complete problem. n A job 1 <= j <- N is characterized by ¨ Ci S 5 completion time of job j under schedule S ¨ pi processing time ¨ ri release time ; the time when the job is available for processing ¨ di due time ; the time when the job should be completed. ui =0 if Ci S <= di and ui =1 otherwise ¨ Lj = Ci S - di & lateness n A schedule S is characterized by ¨ The makespan Cmax = max Ci S ¨ Average completion time = N j S j C N 1 1 44
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Lecture 20 8/1/11 Scheduling objectives n Performance metrics:
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This note was uploaded on 07/30/2011 for the course COP 4600 taught by Professor Montagne during the Spring '08 term at University of Central Florida.

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Lecture20nFull - COT 4600 Operating Systems Spring 2011...

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