Book Image

Mastering Embedded Linux Programming - Third Edition

By : Frank Vasquez, Chris Simmonds
5 (3)
Book Image

Mastering Embedded Linux Programming - Third Edition

5 (3)
By: Frank Vasquez, Chris Simmonds

Overview of this book

If you’re looking for a book that will demystify embedded Linux, then you’ve come to the right place. Mastering Embedded Linux Programming is a fully comprehensive guide that can serve both as means to learn new things or as a handy reference. The first few chapters of this book will break down the fundamental elements that underpin all embedded Linux projects: the toolchain, the bootloader, the kernel, and the root filesystem. After that, you will learn how to create each of these elements from scratch and automate the process using Buildroot and the Yocto Project. As you progress, the book will show you how to implement an effective storage strategy for flash memory chips and install updates to a device remotely once it’s deployed. You’ll also learn about the key aspects of writing code for embedded Linux, such as how to access hardware from apps, the implications of writing multi-threaded code, and techniques to manage memory in an efficient way. The final chapters demonstrate how to debug your code, whether it resides in apps or in the Linux kernel itself. You’ll also cover the different tracers and profilers that are available for Linux so that you can quickly pinpoint any performance bottlenecks in your system. By the end of this Linux book, you’ll be able to create efficient and secure embedded devices using Linux.
Table of Contents (27 chapters)
1
Section 1: Elements of Embedded Linux
10
Section 2: System Architecture and Design Decisions
18
Section 3: Writing Embedded Applications
22
Section 4: Debugging and Optimizing Performance

Chapter 21: Real-Time Programming

Much of the interaction between a computer system and the real world happens in real time, and so this is an important topic for developers of embedded systems. I have touched on real-time programming in several places so far: in Chapter 17, Learning About Processes and Threads, we looked at scheduling policies and priority inversion, and in Chapter 18, Managing Memory, I described the problems with page faults and the need for memory locking. Now it is time to bring these topics together and look at real-time programming in some depth.

In this chapter, I will begin with a discussion about the characteristics of real-time systems, and then consider the implications for system design, at both the application and kernel levels. I will describe the real-time PREEMPT_RT kernel patch, and show how to get it and apply it to a mainline kernel. The final sections will describe how to characterize system latencies using two tools: cyclictest and Ftrace.

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