Multithreaded Processes - Operating Systems, Distributed Computation - Lecture Slides, Slides of Operating Systems

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THREADS

Overview Multithreading Models Threading Issues Pthreads Solaris 2 Threads Windows 2000 Threads Linux Threads Java Threads

Single and Multithreaded Processes

User Threads

• Thread management done by user-level threads library
• Examples
  • POSIX Threads (Pthreads)
  • Mach C-threads
  • Solaris threads

Kernel Threads

• Supported by the Kernel
• Examples
  • Windows 95/98/NT/
  • Solaris
  • Tru64 UNIX
  • BeOS
  • Linux

Many-to-One

• Many user-level threads mapped to single kernel thread.
• Used on systems that do not support kernel threads.

Many-to-One Model

One-to-one Model

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

Threading Issues

• Semantics of fork() and exec() system calls.
• Thread cancellation.
• Signal handling
• Thread pools
• Thread specific data

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.

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

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)

Java Thread States