Mutual Exclusion and Synchronization
|
|
- Candice Ferguson
- 6 years ago
- Views:
Transcription
1 Mutual Exclusion and Synchronization
2 Concurrency Defined Single processor multiprogramming system Interleaving of processes Multiprocessor systems Processes run in parallel on different processors Interleaving and overlapping of processes 2
3 Why concurrency? Communication among processes Synchronization of multiple processes Allocation of processor time Efficient utilization of processor Sharing resources Better system performance 3
4 Concurrency arise in these contexts Three different contexts Multiple applications Multiprogramming Structured application Application can be a set of concurrent processes Operating- system structure Operating system is a set of processes or threads 4
5 Difficul7es of Concurrency Sharing of global resources Operating system managing the allocation of resources optimally Difficult to locate programming errors Relative speed of execution of processes cannot be predicted 5
6 Race Condi7on Shared (Global) int x = 1; Process A Process B x = x + 1; x = x + 1; CPU <<<<< Process A executing >>>>> 1) Load R1,x <<<<< Interrupt; Process Switch to Process B>>>>> 1) Load R1,x 2) Inc R1 3) Store R1,x <<<<< Interrupt; Process Switch to Process A>>>>> 2) Inc R1 3) Store R1,x 6
7 Race Condi7on A condition where two or more threads/processes modify a shared resource and the final result depends on the relative timing of their execution. 7
8 Opera7ng System Concerns Result of processing must be independent of the speed of execution Process Interactions: Processes unaware of each other Compete for resources Process directly aware of each other Cooperation by communication Processes indirectly aware of each other Cooperation by sharing 8
9 Compe77on for Resources Problem: Execution of one process may affect the behavior of competing processes Solution: Mutual Exclusion a critical section is the fragment of code that accesses shared data when one process is executing in its critical section, no other process is allowed to execute in its critical section Issue: Deadlock and Starvation blocked process will never get access to the resource and never terminate 9
10 Coopera7on by Communica7on Communication provides a way to synchronize, or coordinate, the various activities no sharing => mutual exclusion not required Possible to have deadlock each process waiting for a message from the other process Possible to have starvation two processes sending message to each other while another process waits for a message 10
11 Coopera7on by Sharing Processes use and update shared data such as shared variables, files, and data bases Writing must be mutually exclusive Critical sections are used to provide data integrity 11
12 A simple example void echo() { chin = getchar(); chout = chin; putchar(chout); } Q1 12
13 A Simple Example Process P1 Process P2.. chin = getchar();.. chin = getchar(); chout = chin; chout = chin; putchar(chout);.. putchar(chout);.. 13
14 What s causing the problem? Shared variables and shared resources Process or thread behavior must be predictable Process or thread behavior must be independent of the speed of this or other processes or threads 14
15 How to prevent the problem? Restricted access to shared variables and resources Implementing critical section Requiring mutual execution Q2 15
16 Mutual Exclusion Requirements Mutually exclusive access to critical section Progress. If no process is executing in its critical section and there exist some processes that wish to enter their critical section, then the selection of the processes that will enter the critical section next cannot be postponed indefinitely. Bounded Waiting. A bound must exist on the # of times that other processes are allowed to enter their critical sections after a process has requested to enter its critical section and before that request is granted. Assume each process executes at a nonzero speed No assumption concerning relative speed of n processes. 16
17 Four different approaches Hardware support Software- defined approaches Support from the OS Support from the programming language 17
18 Enforcing Mutual Exclusion funtion(){ <non- critical section> enter_critical_section(); <critical section> exit_critical_section(); <remainder section> } 18
19 Hardware Support one void func(){ <non- critical section> /* disable interrupts */ <critical section> /* enable interrupts */ <remainder section> } 19
20 Hardware Support one Interrupt Disabling A process runs until it invokes an operating system service or until it is terminated Disabling interrupts guarantees mutual exclusion On a uniprocessor system Processor is limited in its ability to interleave programs Multiprocessing disabling interrupts on one processor will not guarantee mutual exclusion 20
21 Disadvantages If the critical section is long, then control is taken away from the OS for a long period of time. This decreases overall system performance. Will not work on multi- processor systems. 21
22 Hardware Support two Special Machine Instructions Performed in a single instruction cycle (atomic) Access to the shared memory location is blocked for any other instructions 22
23 Hardware Support two (2) (Return original value of lock) boolean TestAndSet (int lock) { boolean tmp = lock; lock = 1; return tmp; } TestAndSet(Lock) Semantics If TestAndSet(Lock) = 1, someone else already has the lock If TestAndSet(Lock) = 0, lock is free and is set to 1 by the call TestAndSet(Lock) Usage (Spin- Lock) 23
24 Mutual Exclusion with Test- and- Set Shared data: int lock = 0; Process P i do { <non- critical section> while (TestAndSet(lock) == 1) continue; // do nothing, spin (busy wait) <critical section> lock = 0; <remainder section> } while (1); Q3 24
25 Proper7es Of Hardware Support (2) Advantages Applicable to any number of processes and any number of processors Simple and easy to verify Can support multiple critical sections (associate a different variable to each critical section) 25
26 Proper7es Of Hardware Support (2) Disadvantages Busy waiting wastes processor cycles (just like software- only solutions) Starvation is possible because of arbitrary selection of waiting process Deadlock is possible Need alternative mechanisms 26
Concurrency: Mutual Exclusion and Synchronization. Concurrency
Concurrency: Mutual Exclusion and Synchronization Chapter 5 1 Concurrency Multiple applications Structured applications Operating system structure 2 1 Concurrency 3 Difficulties of Concurrency Sharing
More informationConcurrency, Mutual Exclusion and Synchronization C H A P T E R 5
Concurrency, Mutual Exclusion and Synchronization C H A P T E R 5 Multiple Processes OS design is concerned with the management of processes and threads: Multiprogramming Multiprocessing Distributed processing
More informationProcess Synchronization
Process Synchronization Concurrent access to shared data may result in data inconsistency Multiple threads in a single process Maintaining data consistency requires mechanisms to ensure the orderly execution
More informationChapter 5: Process Synchronization. Operating System Concepts 9 th Edition
Chapter 5: Process Synchronization Silberschatz, Galvin and Gagne 2013 Chapter 5: Process Synchronization Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Mutex Locks
More informationPrinciples of Operating Systems CS 446/646
Principles of Operating Systems CS 446/646 2. Processes a. Process Description & Control b. Threads c. Concurrency Types of process interaction Mutual exclusion by busy waiting Mutual exclusion & synchronization
More informationCS420: Operating Systems. Process Synchronization
Process Synchronization James Moscola Department of Engineering & Computer Science York College of Pennsylvania Based on Operating System Concepts, 9th Edition by Silberschatz, Galvin, Gagne Background
More informationProcess Synchronization - I
CSE 421/521 - Operating Systems Fall 2013 Lecture - VIII Process Synchronization - I Tevfik Koşar University at uffalo September 26th, 2013 1 Roadmap Process Synchronization Race Conditions Critical-Section
More informationThe concept of concurrency is fundamental to all these areas.
Chapter 5 Concurrency(I) The central themes of OS are all concerned with the management of processes and threads: such as multiprogramming, multiprocessing, and distributed processing. The concept of concurrency
More informationDept. of CSE, York Univ. 1
EECS 3221.3 Operating System Fundamentals No.5 Process Synchronization(1) Prof. Hui Jiang Dept of Electrical Engineering and Computer Science, York University Background: cooperating processes with shared
More informationMS Windows Concurrency Mechanisms Prepared By SUFIAN MUSSQAA AL-MAJMAIE
MS Windows Concurrency Mechanisms Prepared By SUFIAN MUSSQAA AL-MAJMAIE 163103058 April 2017 Basic of Concurrency In multiple processor system, it is possible not only to interleave processes/threads but
More informationChapter 6: Synchronization. Operating System Concepts 8 th Edition,
Chapter 6: Synchronization, Silberschatz, Galvin and Gagne 2009 Outline Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Semaphores Classic Problems of Synchronization
More informationOperating Systems. Designed and Presented by Dr. Ayman Elshenawy Elsefy
Operating Systems Designed and Presented by Dr. Ayman Elshenawy Elsefy Dept. of Systems & Computer Eng.. AL-AZHAR University Website : eaymanelshenawy.wordpress.com Email : eaymanelshenawy@yahoo.com Reference
More informationCHAPTER 6: PROCESS SYNCHRONIZATION
CHAPTER 6: PROCESS SYNCHRONIZATION The slides do not contain all the information and cannot be treated as a study material for Operating System. Please refer the text book for exams. TOPICS Background
More informationProcess Synchronization
CSC 4103 - Operating Systems Spring 2007 Lecture - VI Process Synchronization Tevfik Koşar Louisiana State University February 6 th, 2007 1 Roadmap Process Synchronization The Critical-Section Problem
More informationChapter 6: Process Synchronization
Chapter 6: Process Synchronization Chapter 6: Synchronization 6.1 Background 6.2 The Critical-Section Problem 6.3 Peterson s Solution 6.4 Synchronization Hardware 6.5 Mutex Locks 6.6 Semaphores 6.7 Classic
More informationChapter 6: Synchronization. Chapter 6: Synchronization. 6.1 Background. Part Three - Process Coordination. Consumer. Producer. 6.
Part Three - Process Coordination Chapter 6: Synchronization 6.1 Background Concurrent access to shared data may result in data inconsistency Maintaining data consistency requires mechanisms to ensure
More informationLecture 6. Process Synchronization
Lecture 6 Process Synchronization 1 Lecture Contents 1. Principles of Concurrency 2. Hardware Support 3. Semaphores 4. Monitors 5. Readers/Writers Problem 2 1. Principles of Concurrency OS design issue
More informationChapter 5: Process Synchronization. Operating System Concepts Essentials 2 nd Edition
Chapter 5: Process Synchronization Silberschatz, Galvin and Gagne 2013 Chapter 5: Process Synchronization Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Mutex Locks
More informationCS370 Operating Systems
CS370 Operating Systems Colorado State University Yashwant K Malaiya Fall 2017 Lecture 11 Slides based on Text by Silberschatz, Galvin, Gagne Various sources 1 1 FAQ Multilevel Feedback Queue: Q0, Q1,
More informationEnforcing Mutual Exclusion Using Monitors
Enforcing Mutual Exclusion Using Monitors Mutual Exclusion Requirements Mutually exclusive access to critical section Progress. If no process is executing in its critical section and there exist some processes
More informationIV. Process Synchronisation
IV. Process Synchronisation Operating Systems Stefan Klinger Database & Information Systems Group University of Konstanz Summer Term 2009 Background Multiprogramming Multiple processes are executed asynchronously.
More informationIT 540 Operating Systems ECE519 Advanced Operating Systems
IT 540 Operating Systems ECE519 Advanced Operating Systems Prof. Dr. Hasan Hüseyin BALIK (5 th Week) (Advanced) Operating Systems 5. Concurrency: Mutual Exclusion and Synchronization 5. Outline Principles
More informationProcess Synchronization
Process Synchronization Chapter 6 2015 Prof. Amr El-Kadi Background Concurrent access to shared data may result in data inconsistency Maintaining data consistency requires mechanisms to ensure the orderly
More informationCONCURRENCY:MUTUAL EXCLUSION AND SYNCHRONIZATION
M05_STAL6329_06_SE_C05.QXD 2/21/08 9:25 PM Page 205 CHAPTER CONCURRENCY:MUTUAL EXCLUSION AND SYNCHRONIZATION 5.1 Principles of Concurrency A Simple Example Race Condition Operating System Concerns Process
More informationChapter 7: Process Synchronization!
Chapter 7: Process Synchronization Background The Critical-Section Problem Synchronization Hardware Semaphores Classical Problems of Synchronization Monitors 7.1 Background Concurrent access to shared
More informationChapter 5 Concurrency: Mutual Exclusion. and. Synchronization. Operating Systems: Internals. and. Design Principles
Operating Systems: Internals and Design Principles Chapter 5 Concurrency: Mutual Exclusion and Synchronization Seventh Edition By William Stallings Designing correct routines for controlling concurrent
More informationChapter 5 Concurrency: Mutual Exclusion and Synchronization
Operating Systems: Internals and Design Principles Chapter 5 Concurrency: Mutual Exclusion and Synchronization Seventh Edition By William Stallings Designing correct routines for controlling concurrent
More informationSynchronization. Race Condition. The Critical-Section Problem Solution. The Synchronization Problem. Typical Process P i. Peterson s Solution
Race Condition Synchronization CSCI 315 Operating Systems Design Department of Computer Science A race occurs when the correctness of a program depends on one thread reaching point x in its control flow
More informationLesson 6: Process Synchronization
Lesson 6: Process Synchronization Chapter 5: Process Synchronization Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Mutex Locks Semaphores Classic Problems of Synchronization
More informationConcurrency: Mutual Exclusion and
Concurrency: Mutual Exclusion and Synchronization 1 Needs of Processes Allocation of processor time Allocation and sharing resources Communication among processes Synchronization of multiple processes
More informationSynchronization Principles
Synchronization Principles Gordon College Stephen Brinton The Problem with Concurrency Concurrent access to shared data may result in data inconsistency Maintaining data consistency requires mechanisms
More informationProcess Coordination
Process Coordination Why is it needed? Processes may need to share data More than one process reading/writing the same data (a shared file, a database record, ) Output of one process being used by another
More informationChapter 7: Process Synchronization. Background. Illustration
Chapter 7: Process Synchronization Background The Critical-Section Problem Synchronization Hardware Semaphores Classical Problems of Synchronization Critical Regions Monitors Synchronization in Solaris
More informationOperating Systems. Lecture 4 - Concurrency and Synchronization. Master of Computer Science PUF - Hồ Chí Minh 2016/2017
Operating Systems Lecture 4 - Concurrency and Synchronization Adrien Krähenbühl Master of Computer Science PUF - Hồ Chí Minh 2016/2017 Mutual exclusion Hardware solutions Semaphores IPC: Message passing
More informationChapter 6: Process Synchronization. Operating System Concepts 8 th Edition,
Chapter 6: Process Synchronization, Silberschatz, Galvin and Gagne 2009 Module 6: Process Synchronization Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Semaphores
More informationChapter 6: Process Synchronization. Module 6: Process Synchronization
Chapter 6: Process Synchronization Module 6: Process Synchronization Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Semaphores Classic Problems of Synchronization
More informationChapter 5: Process Synchronization. Operating System Concepts 9 th Edition
Chapter 5: Process Synchronization Silberschatz, Galvin and Gagne 2013 Chapter 5: Process Synchronization Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Mutex Locks
More informationProcess Synchronization
Chapter 7 Process Synchronization 1 Chapter s Content Background The Critical-Section Problem Synchronization Hardware Semaphores Classical Problems of Synchronization Critical Regions Monitors 2 Background
More informationChapter 7: Process Synchronization. Background
Chapter 7: Process Synchronization Background The Critical-Section Problem Synchronization Hardware Semaphores Classical Problems of Synchronization Critical Regions Monitors Synchronization in Solaris
More informationLecture Topics. Announcements. Today: Concurrency: Mutual Exclusion (Stallings, chapter , 5.7)
Lecture Topics Today: Concurrency: Mutual Exclusion (Stallings, chapter 5.1-5.4, 5.7) Next: Concurrency: Deadlock and Starvation (Stallings, chapter 6.1, 6.6-6.8) 1 Announcements Self-Study Exercise #5
More informationLast class: Today: CPU Scheduling. Start synchronization
Last class: CPU Scheduling Today: Start synchronization Synchronization Processes (threads) share resources. How do processes share resources? How do threads share resources? It is important to coordinate
More informationProcess Synchronization
TDDI04 Concurrent Programming, Operating Systems, and Real-time Operating Systems Process Synchronization [SGG7] Chapter 6 Copyright Notice: The lecture notes are mainly based on Silberschatz s, Galvin
More informationChapter 6: Process Synchronization
Chapter 6: Process Synchronization Chapter 6: Process Synchronization Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Mutex Locks Semaphores Classic Problems of Synchronization
More informationBackground. The Critical-Section Problem Synchronisation Hardware Inefficient Spinning Semaphores Semaphore Examples Scheduling.
Background The Critical-Section Problem Background Race Conditions Solution Criteria to Critical-Section Problem Peterson s (Software) Solution Concurrent access to shared data may result in data inconsistency
More informationModule 6: Process Synchronization
Module 6: Process Synchronization Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Semaphores Classic Problems of Synchronization Monitors Synchronization Examples Atomic
More informationBackground. Old Producer Process Code. Improving the Bounded Buffer. Old Consumer Process Code
Old Producer Process Code Concurrent access to shared data may result in data inconsistency Maintaining data consistency requires mechanisms to ensure the orderly execution of cooperating processes Our
More informationChapter 6: Process Synchronization
Chapter 6: Process Synchronization Objectives Introduce Concept of Critical-Section Problem Hardware and Software Solutions of Critical-Section Problem Concept of Atomic Transaction Operating Systems CS
More informationSynchronization for Concurrent Tasks
Synchronization for Concurrent Tasks Minsoo Ryu Department of Computer Science and Engineering 2 1 Race Condition and Critical Section Page X 2 Algorithmic Approaches Page X 3 Hardware Support Page X 4
More informationProcess Synchronization: Semaphores. CSSE 332 Operating Systems Rose-Hulman Institute of Technology
Process Synchronization: Semaphores CSSE 332 Operating Systems Rose-Hulman Institute of Technology Critical-section problem solution 1. Mutual Exclusion - If process Pi is executing in its critical section,
More informationSynchronization Spinlocks - Semaphores
CS 4410 Operating Systems Synchronization Spinlocks - Semaphores Summer 2013 Cornell University 1 Today How can I synchronize the execution of multiple threads of the same process? Example Race condition
More informationConcurrency: Mutual Exclusion and Synchronization
Concurrency: Mutual Exclusion and Synchronization 1 Needs of Processes Allocation of processor time Allocation and sharing resources Communication among processes Synchronization of multiple processes
More informationProcess Synchronisation (contd.) Deadlock. Operating Systems. Spring CS5212
Operating Systems Spring 2009-2010 Outline Process Synchronisation (contd.) 1 Process Synchronisation (contd.) 2 Announcements Presentations: will be held on last teaching week during lectures make a 20-minute
More informationConcurrency. Chapter 5
Concurrency 1 Chapter 5 2 Concurrency Is a fundamental concept in operating system design Processes execute interleaved in time on a single processor Creates the illusion of simultaneous execution Benefits
More informationConcurrency(I) Chapter 5
Chapter 5 Concurrency(I) The central themes of OS are all concerned with the management of processes and threads: such as multiprogramming, multiprocessing, and distributed processing. The concept of concurrency
More informationChapter 5: Process Synchronization
Chapter 5: Process Synchronization Silberschatz, Galvin and Gagne 2013 Operating System Concepts 9th Edition Chapter 5: Process Synchronization Background The Critical-Section Problem Peterson s Solution
More informationChapter 5: Process Synchronization. Operating System Concepts 9 th Edition
Chapter 5: Process Synchronization Silberschatz, Galvin and Gagne 2013 Chapter 5: Process Synchronization Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Mutex Locks
More informationProcess Synchronization. Mehdi Kargahi School of ECE University of Tehran Spring 2008
Process Synchronization Mehdi Kargahi School of ECE University of Tehran Spring 2008 Producer-Consumer (Bounded Buffer) Producer Consumer Race Condition Producer Consumer Critical Sections Structure of
More informationModule 6: Process Synchronization. Operating System Concepts with Java 8 th Edition
Module 6: Process Synchronization 6.1 Silberschatz, Galvin and Gagne 2009 Module 6: Process Synchronization Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Semaphores
More informationCSE Traditional Operating Systems deal with typical system software designed to be:
CSE 6431 Traditional Operating Systems deal with typical system software designed to be: general purpose running on single processor machines Advanced Operating Systems are designed for either a special
More informationIntroduction to Operating Systems
Introduction to Operating Systems Lecture 4: Process Synchronization MING GAO SE@ecnu (for course related communications) mgao@sei.ecnu.edu.cn Mar. 18, 2015 Outline 1 The synchronization problem 2 A roadmap
More informationCS604 - Operating System Solved Subjective Midterm Papers For Midterm Exam Preparation
CS604 - Operating System Solved Subjective Midterm Papers For Midterm Exam Preparation The given code is as following; boolean flag[2]; int turn; do { flag[i]=true; turn=j; while(flag[j] && turn==j); critical
More informationChapter 6: Process Synchronization. Operating System Concepts 8 th Edition,
Chapter 6: Process Synchronization, Silberschatz, Galvin and Gagne 2009 Module 6: Process Synchronization Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Semaphores
More informationRoadmap. Shared Variables: count=0, buffer[] Producer: Background. Consumer: while (1) { Race Condition. Race Condition.
CSE / - Operating Systems Fall 0 Lecture - VIII Process Synchronization - I Tevfik Koşar Roadmap Process Synchronization s Critical-Section Problem Solutions to Critical Section Different Implementations
More informationCS370 Operating Systems
CS370 Operating Systems Colorado State University Yashwant K Malaiya Spring 1018 L11 Synchronization Slides based on Text by Silberschatz, Galvin, Gagne Various sources 1 1 FAQ Multilevel feedback queue:
More informationProcess Synchronization
Process Synchronization Concurrent access to shared data in the data section of a multi-thread process, in the shared memory of multiple processes, or in a shared file Although every example in this chapter
More informationDr. D. M. Akbar Hussain DE5 Department of Electronic Systems
Concurrency 1 Concurrency Execution of multiple processes. Multi-programming: Management of multiple processes within a uni- processor system, every system has this support, whether big, small or complex.
More informationSynchronization I. Jo, Heeseung
Synchronization I Jo, Heeseung Today's Topics Synchronization problem Locks 2 Synchronization Threads cooperate in multithreaded programs To share resources, access shared data structures Also, to coordinate
More informationConcurrency Control. Synchronization. Brief Preview of Scheduling. Motivating Example. Motivating Example (Cont d) Interleaved Schedules
Brief Preview of Scheduling Concurrency Control Nan Niu (nn@cs.toronto.edu) CSC309 -- Summer 2008 Multiple threads ready to run Some mechanism for switching between them Context switches Some policy for
More informationProcess Management And Synchronization
Process Management And Synchronization In a single processor multiprogramming system the processor switches between the various jobs until to finish the execution of all jobs. These jobs will share the
More informationCOP 4225 Advanced Unix Programming. Synchronization. Chi Zhang
COP 4225 Advanced Unix Programming Synchronization Chi Zhang czhang@cs.fiu.edu 1 Cooperating Processes Independent process cannot affect or be affected by the execution of another process. Cooperating
More informationOperating Systems CMPSC 473. Synchronization February 21, Lecture 11 Instructor: Trent Jaeger
Operating Systems CMPSC 473 Synchronization February 21, 2008 - Lecture 11 Instructor: Trent Jaeger Last class: CPU Scheduling Today: A little more scheduling Start synchronization Little s Law Evaluating
More informationDealing with Issues for Interprocess Communication
Dealing with Issues for Interprocess Communication Ref Section 2.3 Tanenbaum 7.1 Overview Processes frequently need to communicate with other processes. In a shell pipe the o/p of one process is passed
More informationProcess/Thread Synchronization
CSE325 Principles of Operating Systems Process/Thread Synchronization David Duggan dduggan@sandia.gov February 14, 2013 Reading Assignment 7 Chapter 7 Deadlocks, due 2/21 2/14/13 CSE325: Synchronization
More informationChapter 6 Process Synchronization
Chapter 6 Process Synchronization Cooperating Process process that can affect or be affected by other processes directly share a logical address space (threads) be allowed to share data via files or messages
More informationInterprocess Communication By: Kaushik Vaghani
Interprocess Communication By: Kaushik Vaghani Background Race Condition: A situation where several processes access and manipulate the same data concurrently and the outcome of execution depends on the
More informationLecture 5: Synchronization w/locks
Lecture 5: Synchronization w/locks CSE 120: Principles of Operating Systems Alex C. Snoeren Lab 1 Due 10/19 Threads Are Made to Share Global variables and static objects are shared Stored in the static
More informationProcess Synchronization (Part I)
Process Synchronization (Part I) Amir H. Payberah amir@sics.se Amirkabir University of Technology (Tehran Polytechnic) Amir H. Payberah (Tehran Polytechnic) Process Synchronization 1393/7/14 1 / 44 Motivation
More informationMaximum CPU utilization obtained with multiprogramming. CPU I/O Burst Cycle Process execution consists of a cycle of CPU execution and I/O wait
Basic Concepts Scheduling Criteria Scheduling Algorithms Multiple-Processor Scheduling Real-Time Scheduling Thread Scheduling Operating Systems Examples Java Thread Scheduling Algorithm Evaluation CPU
More informationProcess Synchronization
Process Synchronization Daniel Mosse (Slides are from Silberschatz, Galvin and Gagne 2013 and Sherif Khattab) Chapter 5: Process Synchronization Background The Critical-Section Problem Peterson s Solution
More information1. Motivation (Race Condition)
COSC4740-01 Operating Systems Design, Fall 2004, Byunggu Yu Chapter 6 Process Synchronization (textbook chapter 7) Concurrent access to shared data in the data section of a multi-thread process, in the
More informationWhat is the Race Condition? And what is its solution? What is a critical section? And what is the critical section problem?
What is the Race Condition? And what is its solution? Race Condition: Where several processes access and manipulate the same data concurrently and the outcome of the execution depends on the particular
More informationConcurrent Processes Rab Nawaz Jadoon
Concurrent Processes Rab Nawaz Jadoon DCS COMSATS Institute of Information Technology Assistant Professor COMSATS Lahore Pakistan Operating System Concepts Concurrent Processes If more than one threads
More informationConcept of a process
Concept of a process In the context of this course a process is a program whose execution is in progress States of a process: running, ready, blocked Submit Ready Running Completion Blocked Concurrent
More informationAchieving Synchronization or How to Build a Semaphore
Achieving Synchronization or How to Build a Semaphore CS 241 March 12, 2012 Copyright University of Illinois CS 241 Staff 1 Announcements MP5 due tomorrow Jelly beans... Today Building a Semaphore If time:
More informationPESIT Bangalore South Campus Hosur road, 1km before Electronic City, Bengaluru -100 Department of MCA
SOLUTION SET- TEST 2 Subject & Code : Operating System (16MCA24) Name of faculty : Ms. Richa Sharma Max Marks: 40 1 Explain in detail Symmetric multiprocessing 8 2 Explain in detail principles of concurrency
More informationSynchronization I. Jin-Soo Kim Computer Systems Laboratory Sungkyunkwan University
Synchronization I Jin-Soo Kim (jinsookim@skku.edu) Computer Systems Laboratory Sungkyunkwan University http://csl.skku.edu Today s Topics Synchronization problem Locks 2 Synchronization Threads cooperate
More informationChapter 6: Process Synchronization
Module 6: Process Synchronization Chapter 6: Process Synchronization Background! The Critical-Section Problem! Peterson s Solution! Synchronization Hardware! Semaphores! Classic Problems of Synchronization!
More informationCS 333 Introduction to Operating Systems. Class 3 Threads & Concurrency. Jonathan Walpole Computer Science Portland State University
CS 333 Introduction to Operating Systems Class 3 Threads & Concurrency Jonathan Walpole Computer Science Portland State University 1 The Process Concept 2 The Process Concept Process a program in execution
More informationUNIX Input/Output Buffering
UNIX Input/Output Buffering When a C/C++ program begins execution, the operating system environment is responsible for opening three files and providing file pointers to them: stdout standard output stderr
More informationChapter 5: Process Synchronization
Chapter 5: Process Synchronization Silberschatz, Galvin and Gagne 2013! Chapter 5: Process Synchronization Background" The Critical-Section Problem" Petersons Solution" Synchronization Hardware" Mutex
More informationResource management. Real-Time Systems. Resource management. Resource management
Real-Time Systems Specification Implementation Verification Mutual exclusion is a general problem that exists at several levels in a real-time system. Shared resources internal to the the run-time system:
More informationChapter 6 Synchronization
Chapter 6 Synchronization Da-Wei Chang CSIE.NCKU Source: Abraham Silberschatz, Peter B. Galvin, and Greg Gagne, "Operating System Concepts", 9th Edition, Wiley. 1 Outline Background The Critical-Section
More informationChapters 5 and 6 Concurrency
Operating Systems: Internals and Design Principles, 6/E William Stallings Chapters 5 and 6 Concurrency Patricia Roy Manatee Community College, Venice, FL 2008, Prentice Hall Concurrency When several processes/threads
More informationCMSC421: Principles of Operating Systems
CMSC421: Principles of Operating Systems Nilanjan Banerjee Assistant Professor, University of Maryland Baltimore County nilanb@umbc.edu http://www.csee.umbc.edu/~nilanb/teaching/421/ Principles of Operating
More informationRecap: Thread. What is it? What does it need (thread private)? What for? How to implement? Independent flow of control. Stack
What is it? Recap: Thread Independent flow of control What does it need (thread private)? Stack What for? Lightweight programming construct for concurrent activities How to implement? Kernel thread vs.
More informationConcurrency: Mutual Exclusion (Locks)
Concurrency: Mutual Exclusion (Locks) Questions Answered in this Lecture: What are locks and how do we implement them? How do we use hardware primitives (atomics) to support efficient locks? How do we
More informationChapter 5: Synchronization 1
1 Start of Lecture: January 25, 2014 2 Reminders Assignment 1 is due this Friday at 6:00 p.m. Couple comments about Exercise 1: Thought questions: be honest and sincere about questions you have while reading;
More informationProcess Synchronisation (contd.) Operating Systems. Autumn CS4023
Operating Systems Autumn 2017-2018 Outline Process Synchronisation (contd.) 1 Process Synchronisation (contd.) Synchronization Hardware 6.4 (SGG) Many systems provide hardware support for critical section
More informationLast Class: CPU Scheduling! Adjusting Priorities in MLFQ!
Last Class: CPU Scheduling! Scheduling Algorithms: FCFS Round Robin SJF Multilevel Feedback Queues Lottery Scheduling Review questions: How does each work? Advantages? Disadvantages? Lecture 7, page 1
More informationCS 333 Introduction to Operating Systems. Class 3 Threads & Concurrency. Jonathan Walpole Computer Science Portland State University
CS 333 Introduction to Operating Systems Class 3 Threads & Concurrency Jonathan Walpole Computer Science Portland State University 1 Process creation in UNIX All processes have a unique process id getpid(),
More information