Book Image

Mastering Embedded Linux Programming

By : Chris Simmonds
Book Image

Mastering Embedded Linux Programming

By: Chris Simmonds

Overview of this book

Mastering Embedded Linux Programming takes you through the product cycle and gives you an in-depth description of the components and options that are available at each stage. You will begin by learning about toolchains, bootloaders, the Linux kernel, and how to configure a root filesystem to create a basic working device. You will then learn how to use the two most commonly used build systems, Buildroot and Yocto, to speed up and simplify the development process. Building on this solid base, the next section considers how to make best use of raw NAND/NOR flash memory and managed flash eMMC chips, including mechanisms for increasing the lifetime of the devices and to perform reliable in-field updates. Next, you need to consider what techniques are best suited to writing applications for your device. We will then see how functions are split between processes and the usage of POSIX threads, which have a big impact on the responsiveness and performance of the final device The closing sections look at the techniques available to developers for profiling and tracing applications and kernel code using perf and ftrace.
Table of Contents (22 chapters)
Mastering Embedded Linux Programming
About the Author
About the Reviewers

Chapter 13. Profiling and Tracing

Interactive debugging using a source level debugger, as described in the previous chapter, can give you an insight into the way a program works, but it constrains your view to a small body of code. In this chapter, I will look at the larger picture to see if the system is performing as intended.

Programmers and system designers are notoriously bad at guessing where bottlenecks are. So, if your system has performance issues, it is wise to start by looking at the full system and then work down, using more sophisticated tools. In this chapter I begin with the well-known command, top, as a means of getting an overview. Often the problem can be localized to a single program, which you can analyze using the Linux profiler, perf. If the problem is not so localized and you want to get a broader picture, perf can do that as well. To diagnose problems associated with the kernel, I will describe the trace tools, Ftrace and LTTng, as a means of gathering detailed information...