<?xml version="1.0" encoding="ANSI_X3.4-1968" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>Chapter 1. Introduction</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="The Linux Kernel Tracepoint API" /><link rel="up" href="index.html" title="The Linux Kernel Tracepoint API" /><link rel="prev" href="index.html" title="The Linux Kernel Tracepoint API" /><link rel="next" href="ch02.html" title="Chapter 2. IRQ" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 1. Introduction</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="index.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ch02.html">Next</a></td></tr></table><hr /></div><div class="chapter" title="Chapter 1. Introduction"><div class="titlepage"><div><div><h2 class="title"><a id="intro"></a>Chapter 1. Introduction</h2></div></div></div><p> Tracepoints are static probe points that are located in strategic points throughout the kernel. 'Probes' register/unregister with tracepoints via a callback mechanism. The 'probes' are strictly typed functions that are passed a unique set of parameters defined by each tracepoint. </p><p> From this simple callback mechanism, 'probes' can be used to profile, debug, and understand kernel behavior. There are a number of tools that provide a framework for using 'probes'. These tools include Systemtap, ftrace, and LTTng. </p><p> Tracepoints are defined in a number of header files via various macros. Thus, the purpose of this document is to provide a clear accounting of the available tracepoints. The intention is to understand not only what tracepoints are available but also to understand where future tracepoints might be added. </p><p> The API presented has functions of the form: <code class="function">trace_tracepointname(function parameters)</code>. These are the tracepoints callbacks that are found throughout the code. Registering and unregistering probes with these callback sites is covered in the <code class="filename">Documentation/trace/*</code> directory. </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="index.html">Prev</a> </td><td width="20%" align="center"> </td><td width="40%" align="right"> <a accesskey="n" href="ch02.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">The Linux Kernel Tracepoint API </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 2. IRQ</td></tr></table></div></body></html>