Book Image

Linux System Programming Techniques

By : Jack-Benny Persson
Book Image

Linux System Programming Techniques

By: Jack-Benny Persson

Overview of this book

Linux is the world's most popular open source operating system (OS). Linux System Programming Techniques will enable you to extend the Linux OS with your own system programs and communicate with other programs on the system. The book begins by exploring the Linux filesystem, its basic commands, built-in manual pages, the GNU compiler collection (GCC), and Linux system calls. You'll then discover how to handle errors in your programs and will learn to catch errors and print relevant information about them. The book takes you through multiple recipes on how to read and write files on the system, using both streams and file descriptors. As you advance, you'll delve into forking, creating zombie processes, and daemons, along with recipes on how to handle daemons using systemd. After this, you'll find out how to create shared libraries and start exploring different types of interprocess communication (IPC). In the later chapters, recipes on how to write programs using POSIX threads and how to debug your programs using the GNU debugger (GDB) and Valgrind will also be covered. By the end of this Linux book, you will be able to develop your own system programs for Linux, including daemons, tools, clients, and filters.
Table of Contents (14 chapters)

Making the mutex program more efficient

In the previous recipe, we saw that a threaded program isn't necessarily any faster than a non-threaded program. We also saw that when we introduced mutexes, the program got horribly slow. Much of this slowness is due to switching back and forth and locking and unlocking billions of times.

The solution to all of this locking and unlocking and switching back and forth is to lock and unlock as few times as possible. And also, to update the i variable as few times as possible and do as much work as possible in each thread.

In this recipe, we'll make our threaded program much faster and much more efficient.

Knowing how to write efficient threaded programs will help you stay away from many of the pitfalls when it comes to threading.

Getting ready

In order for this recipe to make sense, it's advised that you complete the two previous recipes in this chapter. Other than that, the same requirements apply here; we need the...