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Chapter 5: Threads

Chapter 5: Threads. Overview Multithreading Models Threading Issues Pthreads Solaris 2 Threads Windows 2000 Threads Linux Threads Java Threads. PROCESS. Single and Multithreaded Processes. BENEFITS. Remote Procedure Call Using Threads. Remote Procedure Call Using Threads.

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Chapter 5: Threads

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  1. Chapter 5: Threads • Overview • Multithreading Models • Threading Issues • Pthreads • Solaris 2 Threads • Windows 2000 Threads • Linux Threads • Java Threads Operating System Concepts

  2. PROCESS Operating System Concepts

  3. Single and Multithreaded Processes Operating System Concepts

  4. Operating System Concepts

  5. BENEFITS Operating System Concepts

  6. Operating System Concepts

  7. Remote Procedure Call Using Threads Operating System Concepts

  8. Remote Procedure Call Using Threads Operating System Concepts

  9. PROCESS VERSUS TREAD CONTEXT SWITCHING PER PROCESS ITEMS PER THREAD ITEMS Address space Program counter Global variables Registers Open files Stack Child processes State Pending alarms Signals, signal handlers Accounting info Operating System Concepts

  10. THREAD STATES Spawn: New thread created Running, Ready: As before Block: Waiting for event. Do the mini-context switch i.e. save and restore registers, PC and SP Unblock: Change state to Ready Finish: Finish the thread within the process Operating System Concepts

  11. Operating System Concepts

  12. Relationship Between Threads and Processes Threads:Process Description Example Systems Traditional UNIX implementations 1:1 Each thread of execution is a unique process with its own address space and resources. A process defines an address space and dynamic resource ownership. Multiple threads may be created and executed within that process. M:1 Windows NT, Solaris, OS/2, OS/390, MACH Operating System Concepts

  13. Relationship Between Threads and Processes Threads:Process Description Example Systems 1:M A thread may migrate from one process environment to another. This allows a thread to be easily moved among distinct systems. Ra (Clouds), Emerald TRIX M:M Combines attributes of M:1 and 1:M cases Operating System Concepts

  14. Operating System Concepts

  15. USER – LEVEL THREADS Operating System Concepts

  16. KERNEL – LEVEL THREADS Operating System Concepts

  17. User Threads • Thread management done by user-level threads library • Examples - POSIX Pthreads - Mach C-threads - Solaris threads Operating System Concepts

  18. Kernel Threads • Supported by the Kernel • Examples - Windows 95/98/NT/2000 - Solaris - Tru64 UNIX - BeOS - Linux Operating System Concepts

  19. Multithreading Models • Many-to-One • One-to-One • Many-to-Many Operating System Concepts

  20. Many-to-One • Many user-level threads mapped to single kernel thread. • Used on systems that do not support kernel threads. Operating System Concepts

  21. Many-to-One Model Operating System Concepts

  22. One-to-One • Each user-level thread maps to kernel thread. • Examples - Windows 95/98/NT/2000 - OS/2 Operating System Concepts

  23. One-to-one Model Operating System Concepts

  24. Many-to-Many Model • Allows many user level threads to be mapped to many kernel threads. • Allows the operating system to create a sufficient number of kernel threads. • Solaris 2 • Windows NT/2000 with the ThreadFiber package Operating System Concepts

  25. Many-to-Many Model Operating System Concepts

  26. Threading Issues • Semantics of fork() and exec() system calls. • Thread cancellation. • Signal handling • Thread pools • Thread specific data Operating System Concepts

  27. Pthreads • a POSIX standard (IEEE 1003.1c) API for thread creation and synchronization. • API specifies behavior of the thread library, implementation is up to development of the library. • Common in UNIX operating systems. Operating System Concepts

  28. Operating System Concepts

  29. /* example – cont. */ Operating System Concepts

  30. Solaris 2 Threads Operating System Concepts

  31. Operating System Concepts

  32. Solaris Process Operating System Concepts

  33. Operating System Concepts

  34. Solaris Thread Execution • Synchronization • Suspension • Preemption • Yielding Operating System Concepts

  35. Windows 2000 Threads • Implements the one-to-one mapping. • Each thread contains - a thread id - register set - separate user and kernel stacks - private data storage area Operating System Concepts

  36. Linux Threads • Linux refers to them as tasks rather than threads. • Thread creation is done through clone() system call. • Clone() allows a child task to share the address space of the parent task (process) Operating System Concepts

  37. Java Threads • Java threads may be created by: • Extending Thread class • Implementing the Runnable interface • Java threads are managed by the JVM. Operating System Concepts

  38. Java Thread States Operating System Concepts

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