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 (16 chapters)
15
Index

Using LTTng

The Linux Trace Toolkit project was started by Karim Yaghmour as a means of tracing kernel activity and was one of the first trace tools generally available for the Linux kernel. Later, Mathieu Desnoyers took up the idea and re-implemented it as the next generation trace tool, LTTng. It was then expanded to cover user space traces as well as the kernel. The project website is at http://lttng.org/ and contains a comprehensive user manual.

LTTng consists of three components:

  • A core session manager
  • A kernel tracer implemented as a group of kernel modules
  • A user space tracer implemented as a library

In addition to those, you will need a trace viewer such as Babeltrace (http://www.efficios.com/babeltrace) or the Eclipse Trace Compaas plug-in to display and filter the raw trace data on the host or target.

LTTng requires a kernel configured with CONFIG_TRACEPOINTS, which is enabled when you select Kernel hacking | Tracers | Kernel Function Tracer.

The description that follows refers to LTTng...