Overview. CMSC 330: Organization of Programming Languages. Concurrency. Multiprocessors. Processes vs. Threads. Computation Abstractions
|
|
- Barbra Glenn
- 5 years ago
- Views:
Transcription
1 CMSC 330: Organization of Programming Languages Multithreaded Programming Patterns in Java CMSC Multiprocessors Description Multiple processing units (multiprocessor) From single microprocessor to large compute clusters Can perform multiple tasks in parallel simultaneously Intel Core 2 Quad processor Pentium Xeon 106K processor IBM BlueGene/L CMSC Concurrency Important & pervasive topic in CS Currently covered in CMSC 132 object-oriented programming II Java threads, data races, synchronization CMSC 313 low level programming / computer systems C pthreads CMSC 411/430 architectures / compilers Instruction level parallelism CMSC 412 operating systems Concurrent processes CMSC 424 database design Concurrent transactions CMSC 433 programming language technologies Advanced synchronization CMSC 451 algorithms Parallel algorithms CMSC Computation Abstractions t1 t2 t1 t3 t2 t1 p1 p2 p3 p4 CPU 1 CPU 2 t4 t5! #"$&% ' ( )*,+*-, Processes vs. Threads int x x int x x.0/ :91 56<=>/ 3?7= = x int x 3=765A56<=>/ 3?7= = BDC E< C 9F=:G/ CMSC CMSC
2 So, What Is a Thread? Implementation View Conceptually Parallel computation occurring within a process Implementation view A program counter and a stack Heap and static area are shared among all threads All programs have at least one thread (main) stack pointer Per-thread stack and instruction pointer Saved in memory when thread suspended Put in hardware / when thread resumes program counter CMSC CMSC Programming Threads Thread creation is inexpensive Threads reside on same physical processor Threads share memory, resources Except for local thread variables Shared-memory programming paradigm Threads communicate via shared data Synchronization used to avoid data races Limited scalability (10 s of threads) Programming Processes Process creation is expensive Request to operating system Processes may reside on separate processors Processes do not share memory Message-passing programming paradigm Messages using I/O streams, sockets, network, files Processes must cooperate to communicate Actions performed to send and receive data Highly scalable (1000 s of processors) CMSC CMSC Programming Languages & Threads Threads are available in many languages C, C++, Java, Ruby, OCaml In older languages (e.g., C and C++), threads are a platform specific add-on Not part of the language specification Implemented as code libraries (e.g., pthreads) In newer languages (e.g., Java, Ruby), threads are part of the language specification Not dependent on operating system Can utilize special keywords, syntax CMSC CMSC
3 Java Threads Review Thread class & Runnable interface Used to create / manipulate threads Run-time scheduler Preemptive / non-premptive Thread states (new, runnable, blocked, dead) Data race Concurrent accesses to same shared object Where at least one access is a write Result may change depending on thread schedule Very difficult to detect & correct Java Threads Review (cont.) Synchronization Locks ensure exclusive access Provides mutual exclusion Only 1 thread can obtain lock at a time Lock associated w/ every Java object Use synchronized keyword to acquire lock Code blocks synchronized (o) { // lock for Object o Methods synchronized foo( ) { // lock for this Thread blocks when trying to acquire locked lock Thread returns when lock is finally acquired May deadlock if threads try to acquire each other s lock CMSC CMSC Synchronization Example (Java 1.4) Thread Creation public class Example extends Thread { private static int cnt = 0 static Object value = new Object() public void run() { int y = cnt cnt = y + 1 Value, any Java object Acquires the lock associated w/ value only succeeds if not held by another thread, otherwise blocks Releases the lock execution (time) main thread thread starts thread join thread starts thread ends CMSC CMSC Creating Threads in Java 1 Thread Class Approach Extend Thread class and override run method Example public class MyT extends Thread { public void run( ) { // work for thread MyT t = new MyT( ) // create thread t.start( ) // begin running thread // thread executing in parallel t.join() // waits for thread to exit CMSC Creating Threads in Java 2 Runnable Approach 1. Define class implementing Runnable interface public interface Runnable { public void run( ) 2. Put work to be performed in run( ) method 3. Create instance of the worker class 4. Create thread to run it Create Thread object Pass worker object to Thread constructor Or hand the worker instance to an executor Alternative methods for running threads CMSC
4 Creating Threads in Java 2 (cont.) Example public class MyT implements Runnable { public void run( ) { // work for thread Thread t = new Thread(new MyT( )) // create thread t.start() // begin running thread // thread executing in parallel t.join() // waits for thread to exit Passing Parameters to Threads run( ) doesn t take parameters We pass parameters to the new thread by storing them as private fields In the Runnable object CMSC CMSC CMSC Producer / Consumer Problem Suppose we are communicating with a shared variable E.g., a fixed size buffer holding messages One thread produces input to the buffer One thread consumes data from the buffer Rules Producer can t add input to the buffer if it s full Consumer can t take input from the buffer if it s empty CMSC Producer / Consumer Idea If buffer is partially full, producer or consumer can run producer If buffer is empty, only producer can run producer c b a If buffer is full, only consumer can run consumer e d c b a consumer Broken Producer/Consumer Example void produce(object o) { while (valueready) while (!valueready) Object o = value Threads wait with lock held no way to make progress CMSC CMSC
5 Broken Producer/Consumer Example void produce(object o) { while (valueready) while (!valueready) Object o = value valueready accessed without a lock held data race CMSC Inefficient Producer/Consumer Example Constantly acquiring / releasing lock busy wait void produce(object o) { boolean done = false while (!done) { if (!valueready) { done = true Object o = null boolean done = false while (!done) { if (valueready) { o = value done = true CMSC Solving Producer / Consumer Problem Difficult to use locks directly Very hard to get right Problems often very subtle Proper approach use condition variables Definition: a set of threads associated w/ a lock Also known as a wait set Waiting for some condition to become true Allows threads to sleep while waiting to acquire lock Can wake up sleeping threads before releasing lock In Java 1.4 Each monitor has a single condition variable CMSC CMSC Wait and NotifyAll (Java 1.4) Use synchronize on object to get associated lock Object o o s lock o s wait set Objects also have an associated wait set Can be viewed as an implicit condition variable CMSC Wait and NotifyAll (cont.) o.wait() Must hold lock associated with o Release that lock And no other locks Adds this thread to wait set for lock Blocks the thread o.notifyall() Must hold lock associated with o Resumes all threads on lock s wait set Those threads must reacquire lock before continuing This is part of the function you don t need to do it explicitly CMSC
6 Producer/Consumer Example void produce(object o) { while (valueready) wait() notifyall() while (!valueready) wait() Object o = value notifyall() Using Correctly wait( ) must be called in a while loop may not be met when await returns Some other thread may have awoken first And changed condition (e.g., consumed item in buffer) Avoid holding other locks when waiting only gives up lock on object you are waiting on Reduces possibility of deadlock CMSC CMSC Broken Producer/Consumer Example void produce(object o) { if (valueready) wait() notifyall() if (!valueready) wait() Object o = value notifyall() Illegal access if multiple producers or consumers CMSC Aspects of Synchronization Atomicity Locking to obtain mutual exclusion What we most often think about Visibility Ensuring that changes to object fields made in one thread are seen in other threads Ordering Ensuring that you aren t surprised by the order in which statements are executed CMSC Key Ideas Multiple threads can run simultaneously Either truly in parallel on a multiprocessor Or can be scheduled on a single processor A running thread can be pre-empted at any time Threads can share data In Java, only fields can be shared Need to prevent data races Rule of thumb 1: You must hold a lock when accessing shared data Rule of thumb 2: You must not release a lock until shared data is in a valid state Overuse use of synchronization can create deadlock Rule of thumb: No deadlock if only one lock CMSC
CMSC 330: Organization of Programming Languages
CMSC 330: Organization of Programming Languages Multithreading Multiprocessors Description Multiple processing units (multiprocessor) From single microprocessor to large compute clusters Can perform multiple
CMSC 330: Organization of Programming Languages
CMSC 330: Organization of Programming Languages Threads Synchronization Refers to mechanisms allowing a programmer to control the execution order of some operations across different threads in a concurrent
Computation Abstractions. CMSC 330: Organization of Programming Languages. So, What Is a Thread? Processes vs. Threads. A computer.
CMSC 330: Organization of Programming Languages Threads Computation Abstractions t1 t2 t1 t3 t2 t1 p1 p2 p3 p4 CPU 1 CPU 2 A computer t4 t5 Processes (e.g., JVM s) Threads CMSC 330 2 Processes vs. Threads
The Dining Philosophers Problem CMSC 330: Organization of Programming Languages
The Dining Philosophers Problem CMSC 0: Organization of Programming Languages Threads Classic Concurrency Problems Philosophers either eat or think They must have two forks to eat Can only use forks on
CMSC 330: Organization of Programming Languages. The Dining Philosophers Problem
CMSC 330: Organization of Programming Languages Threads Classic Concurrency Problems The Dining Philosophers Problem Philosophers either eat or think They must have two forks to eat Can only use forks
CMSC 330: Organization of Programming Languages. Threads Classic Concurrency Problems
: Organization of Programming Languages Threads Classic Concurrency Problems The Dining Philosophers Problem Philosophers either eat or think They must have two forks to eat Can only use forks on either
CMSC 132: Object-Oriented Programming II. Threads in Java
CMSC 132: Object-Oriented Programming II Threads in Java 1 Problem Multiple tasks for computer Draw & display images on screen Check keyboard & mouse input Send & receive data on network Read & write files
Computation Abstractions. Processes vs. Threads. So, What Is a Thread? CMSC 433 Programming Language Technologies and Paradigms Spring 2007
CMSC 433 Programming Language Technologies and Paradigms Spring 2007 Threads and Synchronization May 8, 2007 Computation Abstractions t1 t1 t4 t2 t1 t2 t5 t3 p1 p2 p3 p4 CPU 1 CPU 2 A computer Processes
Overview. Processes vs. Threads. Computation Abstractions. CMSC 433, Fall Michael Hicks 1
CMSC 433 Programming Language Technologies and Paradigms Spring 2003 Threads and Synchronization April 1, 2003 Overview What are threads? Thread scheduling, data races, and synchronization Thread mechanisms
Multi-threaded programming in Java
Multi-threaded programming in Java Java allows program to specify multiple threads of execution Provides instructions to ensure mutual exclusion, and selective blocking/unblocking of threads What is a
CMSC 433 Programming Language Technologies and Paradigms. Concurrency
CMSC 433 Programming Language Technologies and Paradigms Concurrency What is Concurrency? Simple definition Sequential programs have one thread of control Concurrent programs have many Concurrency vs.
CMSC 330: Organization of Programming Languages. Concurrency & Multiprocessing
CMSC 330: Organization of Programming Languages Concurrency & Multiprocessing Multiprocessing Multiprocessing: The use of multiple parallel computations We have entered an era of multiple cores... Hyperthreading
wait with priority An enhanced version of the wait operation accepts an optional priority argument:
wait with priority An enhanced version of the wait operation accepts an optional priority argument: syntax: .wait the smaller the value of the parameter, the highest the priority
Java Threads. COMP 585 Noteset #2 1
Java Threads The topic of threads overlaps the boundary between software development and operation systems. Words like process, task, and thread may mean different things depending on the author and the
Threading and Synchronization. Fahd Albinali
Threading and Synchronization Fahd Albinali Parallelism Parallelism and Pseudoparallelism Why parallelize? Finding parallelism Advantages: better load balancing, better scalability Disadvantages: process/thread
Threads Questions Important Questions
Threads Questions Important Questions https://dzone.com/articles/threads-top-80-interview https://www.journaldev.com/1162/java-multithreading-concurrency-interviewquestions-answers https://www.javatpoint.com/java-multithreading-interview-questions
7. MULTITHREDED PROGRAMMING
7. MULTITHREDED PROGRAMMING What is thread? A thread is a single sequential flow of control within a program. Thread is a path of the execution in a program. Muti-Threading: Executing more than one thread
CS 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(),
CS533 Concepts of Operating Systems. Jonathan Walpole
CS533 Concepts of Operating Systems Jonathan Walpole Introduction to Threads and Concurrency Why is Concurrency Important? Why study threads and concurrent programming in an OS class? What is a thread?
CSE 451: Operating Systems Winter Lecture 7 Synchronization. Steve Gribble. Synchronization. Threads cooperate in multithreaded programs
CSE 451: Operating Systems Winter 2005 Lecture 7 Synchronization Steve Gribble Synchronization Threads cooperate in multithreaded programs to share resources, access shared data structures e.g., threads
Multitasking Multitasking allows several activities to occur concurrently on the computer. A distinction is usually made between: Process-based multit
Threads Multitasking Multitasking allows several activities to occur concurrently on the computer. A distinction is usually made between: Process-based multitasking Thread-based multitasking Multitasking
Need for synchronization: If threads comprise parts of our software systems, then they must communicate.
Thread communication and synchronization There are two main aspects to Outline for Lecture 19 multithreaded programming in Java: I. Thread synchronization. thread lifecycle, and thread synchronization.
CS 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
Introduction to Java Threads
Object-Oriented Programming Introduction to Java Threads RIT CS 1 "Concurrent" Execution Here s what could happen when you run this Java program and launch 3 instances on a single CPU architecture. The
MultiThreading. Object Orientated Programming in Java. Benjamin Kenwright
MultiThreading Object Orientated Programming in Java Benjamin Kenwright Outline Review Essential Java Multithreading Examples Today s Practical Review/Discussion Question Does the following code compile?
Concurrent Programming using Threads
Concurrent Programming using Threads Threads are a control mechanism that enable you to write concurrent programs. You can think of a thread in an object-oriented language as a special kind of system object
Synchronising Threads
Synchronising Threads David Chisnall March 1, 2011 First Rule for Maintainable Concurrent Code No data may be both mutable and aliased Harder Problems Data is shared and mutable Access to it must be protected
G52CON: Concepts of Concurrency
G52CON: Concepts of Concurrency Lecture 11: Semaphores I" Brian Logan School of Computer Science bsl@cs.nott.ac.uk Outline of this lecture" problems with Peterson s algorithm semaphores implementing semaphores
CSE 451: Operating Systems Winter Lecture 7 Synchronization. Hank Levy 412 Sieg Hall
CSE 451: Operating Systems Winter 2003 Lecture 7 Synchronization Hank Levy Levy@cs.washington.edu 412 Sieg Hall Synchronization Threads cooperate in multithreaded programs to share resources, access shared
Chair of Software Engineering. Java and C# in depth. Carlo A. Furia, Marco Piccioni, Bertrand Meyer. Java: concurrency
Chair of Software Engineering Carlo A. Furia, Marco Piccioni, Bertrand Meyer Java: concurrency Outline Java threads thread implementation sleep, interrupt, and join threads that return values Thread synchronization
The New Java Technology Memory Model
The New Java Technology Memory Model java.sun.com/javaone/sf Jeremy Manson and William Pugh http://www.cs.umd.edu/~pugh 1 Audience Assume you are familiar with basics of Java technology-based threads (
Lecture 8: September 30
CMPSCI 377 Operating Systems Fall 2013 Lecture 8: September 30 Lecturer: Prashant Shenoy Scribe: Armand Halbert 8.1 Semaphores A semaphore is a more generalized form of a lock that can be used to regulate
Synchronization 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
27/04/2012. We re going to build Multithreading Application. Objectives. MultiThreading. Multithreading Applications. What are Threads?
Objectives MultiThreading What are Threads? Interrupting threads Thread properties By Võ Văn Hải Faculty of Information Technologies Summer 2012 Threads priorities Synchronization Callables and Futures
Concurrency, Thread. Dongkun Shin, SKKU
Concurrency, Thread 1 Thread Classic view a single point of execution within a program a single PC where instructions are being fetched from and executed), Multi-threaded program Has more than one point
CMSC 132: Object-Oriented Programming II
CMSC 132: Object-Oriented Programming II Synchronization in Java Department of Computer Science University of Maryland, College Park Multithreading Overview Motivation & background Threads Creating Java
Advanced Concepts of Programming
Berne University of Applied Sciences E. Benoist / E. Dubuis January 2005 1 Multithreading in Java Java provides the programmer with built-in threading capabilities The programmer can create and manipulate
CS3733: Operating Systems
Outline CS3733: Operating Systems Topics: Synchronization, Critical Sections and Semaphores (SGG Chapter 6) Instructor: Dr. Tongping Liu 1 Memory Model of Multithreaded Programs Synchronization for coordinated
Week 7. Concurrent Programming: Thread Synchronization. CS 180 Sunil Prabhakar Department of Computer Science Purdue University
Week 7 Concurrent Programming: Thread Synchronization CS 180 Sunil Prabhakar Department of Computer Science Purdue University Announcements Exam 1 tonight 6:30 pm - 7:30 pm MTHW 210 2 Outcomes Understand
Module 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
CS 5523 Operating Systems: Midterm II - reivew Instructor: Dr. Tongping Liu Department Computer Science The University of Texas at San Antonio
CS 5523 Operating Systems: Midterm II - reivew Instructor: Dr. Tongping Liu Department Computer Science The University of Texas at San Antonio Fall 2017 1 Outline Inter-Process Communication (20) Threads
Chapter 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
Multithreaded Programming Part II. CSE 219 Stony Brook University, Department of Computer Science
Multithreaded Programming Part II CSE 219 Stony Brook University, Thread Scheduling In a Java application, main is a thread on its own Once multiple threads are made Runnable the thread scheduler of the
Threads and Java Memory Model
Threads and Java Memory Model Oleg Šelajev @shelajev oleg@zeroturnaround.com October 6, 2014 Agenda Threads Basic synchronization Java Memory Model Concurrency Concurrency - several computations are executing
Part I: Communication and Networking
Review what we learned Part I: Communication and Networking Communication and Networking: Week 5-6, Lectures 2-7 Lecture 1 OSI vs TCP/IP model OSI model Protocols TCP/IP model Application FTP SMTP HTTP
Question Points Score Total 100
Midterm Exam #1 CMSC 433 Programming Language Technologies and Paradigms Spring 2014 March 13, 2014 Guidelines Put your name on each page before starting the exam. Write your answers directly on the exam
Operating Systems CMPSCI 377 Spring Mark Corner University of Massachusetts Amherst
Operating Systems CMPSCI 377 Spring 2017 Mark Corner University of Massachusetts Amherst What is a Monitor? Ties data and the synchronization operations together Monitors guarantee mutual exclusion, i.e.,
JAVA and J2EE UNIT - 4 Multithreaded Programming And Event Handling
JAVA and J2EE UNIT - 4 Multithreaded Programming And Event Handling Multithreaded Programming Topics Multi Threaded Programming What are threads? How to make the classes threadable; Extending threads;
Chapter 32 Multithreading and Parallel Programming
Chapter 32 Multithreading and Parallel Programming 1 Objectives To get an overview of multithreading ( 32.2). To develop task classes by implementing the Runnable interface ( 32.3). To create threads to
Threads Chate Patanothai
Threads Chate Patanothai Objectives Knowing thread: 3W1H Create separate threads Control the execution of a thread Communicate between threads Protect shared data C. Patanothai Threads 2 What are threads?
Multi-threading in Java. Jeff HUANG
Multi-threading in Java Jeff HUANG Software Engineering Group @HKUST Do you use them? 2 Do u know their internals? 3 Let s see File DB How can they service so many clients simultaneously? l 4 Multi-threading
CS 351 Design of Large Programs Threads and Concurrency
CS 351 Design of Large Programs Threads and Concurrency Brooke Chenoweth University of New Mexico Spring 2018 Concurrency in Java Java has basic concurrency support built into the language. Also has high-level
Concurrency & Parallelism. Threads, Concurrency, and Parallelism. Multicore Processors 11/7/17
Concurrency & Parallelism So far, our programs have been sequential: they do one thing after another, one thing at a. Let s start writing programs that do more than one thing at at a. Threads, Concurrency,
Lesson 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
SSC - Concurrency and Multi-threading Java multithreading programming - Synchronisation (II)
SSC - Concurrency and Multi-threading Java multithreading programming - Synchronisation (II) Shan He School for Computational Science University of Birmingham Module 06-19321: SSC Outline Outline of Topics
CMSC 433 Programming Language Technologies and Paradigms. Synchronization
CMSC 433 Programming Language Technologies and Paradigms Synchronization Aspects of Synchronization Atomicity Locking to obtain mutual exclusion What we most often think about Visibility Ensuring that
CS 2112 Lecture 20 Synchronization 5 April 2012 Lecturer: Andrew Myers
CS 2112 Lecture 20 Synchronization 5 April 2012 Lecturer: Andrew Myers 1 Critical sections and atomicity We have been seeing that sharing mutable objects between different threads is tricky We need some
CS61B, Spring 2003 Discussion #17 Amir Kamil UC Berkeley 5/12/03
CS61B, Spring 2003 Discussion #17 Amir Kamil UC Berkeley 5/12/03 Topics: Threading, Synchronization 1 Threading Suppose we want to create an automated program that hacks into a server. Many encryption
Chapter 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
CS 10: Problem solving via Object Oriented Programming Winter 2017
CS 10: Problem solving via Object Oriented Programming Winter 2017 Tim Pierson 260 (255) Sudikoff SynchronizaGon Agenda 1. Threads and interleaving execugon 2. Producer/consumer 3. Deadlock, starvagon
Operating 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
CS11 Java. Fall Lecture 7
CS11 Java Fall 2006-2007 Lecture 7 Today s Topics All about Java Threads Some Lab 7 tips Java Threading Recap A program can use multiple threads to do several things at once A thread can have local (non-shared)
Chapter 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
Java Threads. Written by John Bell for CS 342, Spring 2018
Java Threads Written by John Bell for CS 342, Spring 2018 Based on chapter 9 of Learning Java, Fourth Edition by Niemeyer and Leuck, and other sources. Processes A process is an instance of a running program.
10/17/ Gribble, Lazowska, Levy, Zahorjan 2. 10/17/ Gribble, Lazowska, Levy, Zahorjan 4
Temporal relations CSE 451: Operating Systems Autumn 2010 Module 7 Synchronization Instructions executed by a single thread are totally ordered A < B < C < Absent synchronization, instructions executed
Deadlock and Monitors. CS439: Principles of Computer Systems September 24, 2018
Deadlock and Monitors CS439: Principles of Computer Systems September 24, 2018 Bringing It All Together Processes Abstraction for protection Define address space Threads Share (and communicate) through
CS 571 Operating Systems. Midterm Review. Angelos Stavrou, George Mason University
CS 571 Operating Systems Midterm Review Angelos Stavrou, George Mason University Class Midterm: Grading 2 Grading Midterm: 25% Theory Part 60% (1h 30m) Programming Part 40% (1h) Theory Part (Closed Books):
Recap: 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.
Programming in Parallel COMP755
Programming in Parallel COMP755 All games have morals; and the game of Snakes and Ladders captures, as no other activity can hope to do, the eternal truth that for every ladder you hope to climb, a snake
Concurrency 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
CS333 Intro to Operating Systems. Jonathan Walpole
CS333 Intro to Operating Systems Jonathan Walpole Threads & Concurrency 2 Threads Processes have the following components: - an address space - a collection of operating system state - a CPU context or
THREADS & CONCURRENCY
27/04/2018 Sorry for the delay in getting slides for today 2 Another reason for the delay: Yesterday: 63 posts on the course Piazza yesterday. A7: If you received 100 for correctness (perhaps minus a late
W4118 Operating Systems. Instructor: Junfeng Yang
W4118 Operating Systems Instructor: Junfeng Yang Outline Semaphores Producer-consumer problem Monitors and condition variables 2 Semaphore motivation Problem with lock: mutual exclusion, but no ordering
Review: Easy Piece 1
CS 537 Lecture 10 Threads Michael Swift 10/9/17 2004-2007 Ed Lazowska, Hank Levy, Andrea and Remzi Arpaci-Dussea, Michael Swift 1 Review: Easy Piece 1 Virtualization CPU Memory Context Switch Schedulers
Object Oriented Programming. Week 10 Part 1 Threads
Object Oriented Programming Week 10 Part 1 Threads Lecture Concurrency, Multitasking, Process and Threads Thread Priority and State Java Multithreading Extending the Thread Class Defining a Class that
Threads. Definitions. Process Creation. Process. Thread Example. Thread. From Volume II
Definitions A glossary Threads From Volume II Copyright 1998-2002 Delroy A. Brinkerhoff. All Rights Reserved. Threads Slide 1 of 30 PMultitasking: (concurrent ramming, multiramming) the illusion of running
Performance Throughput Utilization of system resources
Concurrency 1. Why concurrent programming?... 2 2. Evolution... 2 3. Definitions... 3 4. Concurrent languages... 5 5. Problems with concurrency... 6 6. Process Interactions... 7 7. Low-level Concurrency
Threads, Concurrency, and Parallelism
Threads, Concurrency, and Parallelism Lecture 24 CS2110 Spring 2017 Concurrency & Parallelism So far, our programs have been sequential: they do one thing after another, one thing at a time. Let s start
Chapter 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
Threads and Parallelism in Java
Threads and Parallelism in Java Java is one of the few main stream programming languages to explicitly provide for user-programmed parallelism in the form of threads. A Java programmer may organize a program
Multitasking. Multitasking allows several activities to occur concurrently on the computer Levels of multitasking: Process based multitasking
Java Thread Multitasking Multitasking allows several activities to occur concurrently on the computer Levels of multitasking: Process based multitasking Allows programs (processes) to run concurrently
INF 212 ANALYSIS OF PROG. LANGS CONCURRENCY. Instructors: Crista Lopes Copyright Instructors.
INF 212 ANALYSIS OF PROG. LANGS CONCURRENCY Instructors: Crista Lopes Copyright Instructors. Basics Concurrent Programming More than one thing at a time Examples: Network server handling hundreds of clients
Synchronization 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
Concurrent Programming Lecture 10
Concurrent Programming Lecture 10 25th September 2003 Monitors & P/V Notion of a process being not runnable : implicit in much of what we have said about P/V and monitors is the notion that a process may
CS510 Operating System Foundations. Jonathan Walpole
CS510 Operating System Foundations Jonathan Walpole Threads & Concurrency 2 Why Use Threads? Utilize multiple CPU s concurrently Low cost communication via shared memory Overlap computation and blocking
Warm-up question (CS 261 review) What is the primary difference between processes and threads from a developer s perspective?
Warm-up question (CS 261 review) What is the primary difference between processes and threads from a developer s perspective? CS 470 Spring 2018 POSIX Mike Lam, Professor Multithreading & Pthreads MIMD
Dealing 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
CS 455: INTRODUCTION TO DISTRIBUTED SYSTEMS [THREADS] Frequently asked questions from the previous class survey
CS 455: INTRODUCTION TO DISTRIBUTED SYSTEMS [THREADS] Threads block when they can t get that lock Wanna have your threads stall? Go ahead, synchronize it all The antidote to this liveness pitfall? Keeping
Contribution:javaMultithreading Multithreading Prof. Dr. Ralf Lämmel Universität Koblenz-Landau Software Languages Team
http://101companies.org/wiki/ Contribution:javaMultithreading Multithreading Prof. Dr. Ralf Lämmel Universität Koblenz-Landau Software Languages Team Non-101samples available here: https://github.com/101companies/101repo/tree/master/technologies/java_platform/samples/javathreadssamples
Java Threads. Introduction to Java Threads
Java Threads Resources Java Threads by Scott Oaks & Henry Wong (O Reilly) API docs http://download.oracle.com/javase/6/docs/api/ java.lang.thread, java.lang.runnable java.lang.object, java.util.concurrent
Concurrent Programming
Concurrency Concurrent Programming A sequential program has a single thread of control. Its execution is called a process. A concurrent program has multiple threads of control. They may be executed as
Chapter 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
Chapter 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
Synchronization. CS 475, Spring 2018 Concurrent & Distributed Systems
Synchronization CS 475, Spring 2018 Concurrent & Distributed Systems Review: Threads: Memory View code heap data files code heap data files stack stack stack stack m1 m1 a1 b1 m2 m2 a2 b2 m3 m3 a3 m4 m4
Synchronization in Java
Synchronization in Java Nelson Padua-Perez Bill Pugh Department of Computer Science University of Maryland, College Park Synchronization Overview Unsufficient atomicity Data races Locks Deadlock Wait /
Operating Systems. Synchronization
Operating Systems Fall 2014 Synchronization Myungjin Lee myungjin.lee@ed.ac.uk 1 Temporal relations Instructions executed by a single thread are totally ordered A < B < C < Absent synchronization, instructions
CS 159: Parallel Processing
Outline: Concurrency using Java CS 159: Parallel Processing Spring 2007 Processes vs Threads Thread basics Synchronization Locks Examples Avoiding problems Immutable objects Atomic operations High"level
Concurrency in Java Prof. Stephen A. Edwards
Concurrency in Java Prof. Stephen A. Edwards The Java Language Developed by James Gosling et al. at Sun Microsystems in the early 1990s Originally called Oak, first intended application was as an OS for
THREADS AND CONCURRENCY
THREADS AND CONCURRENCY Lecture 22 CS2110 Spring 2013 Graphs summary 2 Dijkstra: given a vertex v, finds shortest path from v to x for each vertex x in the graph Key idea: maintain a 5-part invariant on
The University of Texas at Arlington
The University of Texas at Arlington Lecture 10: Threading and Parallel Programming Constraints CSE 5343/4342 Embedded d Systems II Objectives: Lab 3: Windows Threads (win32 threading API) Convert serial