Operating System Concepts Essentials, Second Edition

Threads

The process model introduced in Chapter 3 assumed that a process was an executing program with a single thread of control. Virtually all modern operating systems, however, provide features enabling a process to contain multiple threads of control. In this chapter, we introduce many concepts associated with multithreaded computer systems, including a discussion of the APIs for the Pthreads, Windows, and Java thread libraries. We look at a number of issues related to multithreaded programming and its effect on the design of operating systems. Finally, we explore how the Windows and Linux operating systems support threads at the kernel level.

CHAPTER OBJECTIVES

• To introduce the notion of a thread–a fundamental unit of CPU utilization that forms the basis of multithreaded computer systems.
• To discuss the APIs for the Pthreads, Windows, and Java thread libraries.
• To explore several strategies that provide implicit threading.
• To examine issues related to multithreaded programming.
• To cover operating system support for threads in Windows and Linux.

4.1 Overview

A thread is a basic unit of CPU utilization; it comprises a thread ID, a program counter, a register set, and a stack. It shares with other threads belonging to the same process its code section, data section, and other operating-system resources, such as open files and signals. A traditional (or heavyweight) process ...