modified ch6.ppt - Chapter 6 CPU Scheduling Operating System Concepts – 9th Edition Silberschatz Galvin and Gagne ©2013 Chapter 6 CPU Scheduling

modified ch6.ppt - Chapter 6 CPU Scheduling Operating...

This preview shows page 1 - 11 out of 75 pages.

Silberschatz, Galvin and Gagne ©2013 Operating System Concepts – 9 th Edition Chapter 6: CPU Scheduling
Image of page 1

Subscribe to view the full document.

6.2 Silberschatz, Galvin and Gagne ©2013 Operating System Concepts – 9 th Edition Chapter 6: CPU Scheduling Basic Concepts Scheduling Criteria Scheduling Algorithms Thread Scheduling Multiple-Processor Scheduling Real-Time CPU Scheduling Operating Systems Examples Algorithm Evaluation
Image of page 2
6.3 Silberschatz, Galvin and Gagne ©2013 Operating System Concepts – 9 th Edition Objectives To introduce CPU scheduling, which is the basis for multiprogrammed operating systems To describe various CPU-scheduling algorithms To discuss evaluation criteria for selecting a CPU-scheduling algorithm for a particular system To examine the scheduling algorithms of several operating systems
Image of page 3

Subscribe to view the full document.

6.4 Silberschatz, Galvin and Gagne ©2013 Operating System Concepts – 9 th Edition Basic Concepts Maximum CPU utilization obtained with multiprogramming CPU–I/O Burst Cycle – Process execution consists of a cycle of CPU execution and I/O wait CPU burst followed by I/O burst CPU burst distribution is of main concern
Image of page 4
6.5 Silberschatz, Galvin and Gagne ©2013 Operating System Concepts – 9 th Edition Histogram of CPU-burst Times
Image of page 5

Subscribe to view the full document.

6.6 Silberschatz, Galvin and Gagne ©2013 Operating System Concepts – 9 th Edition CPU Scheduler OS keeps the CPU busy all the time by always select a waiting process from the ready queue to be executed by this CPU. This is carried out by short-term scheduler ( or CPU scheduler) CPU Ready queue Main Memory OS Short-term scheduler
Image of page 6
6.7 Silberschatz, Galvin and Gagne ©2013 Operating System Concepts – 9 th Edition CPU Scheduler Short-term scheduler selects from among the processes in ready queue, and allocates the CPU to one of them Queue may be ordered in various ways CPU scheduling decisions may take place when a process: 1. Switches from running to waiting state 2. Switches from running to ready state 3. Switches from waiting to ready 4. Terminates Scheduling under 1 and 4 is nonpreemptive (once CPU has been allocated to a process, the process keeps CPU until it releases the CPU either by terminating or by switching to the waiting status) All other scheduling is preemptive ( there is a choice of scheduling) Consider access to shared data Consider preemption while in kernel mode Consider interrupts occurring during crucial OS activities
Image of page 7

Subscribe to view the full document.

6.8 Silberschatz, Galvin and Gagne ©2013 Operating System Concepts – 9 th Edition Diagram of Process State
Image of page 8
6.9 Silberschatz, Galvin and Gagne ©2013 Operating System Concepts – 9 th Edition Dispatcher Dispatcher module gives control of the CPU to the process selected by the short-term scheduler ; this involves: switching context switching to user mode jumping to the proper location in the user program to restart that program Dispatch latency – time it takes for the dispatcher to stop one process and start another running
Image of page 9

Subscribe to view the full document.

6.10
Image of page 10
Image of page 11
  • Spring '13
  • JAY HEIZER | BARRY RENDER | CHUCK MUNSON

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Ask Expert Tutors You can ask 0 bonus questions You can ask 0 questions (0 expire soon) You can ask 0 questions (will expire )
Answers in as fast as 15 minutes