1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>Chapter&#160;1.&#160;Introduction</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><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="irq.html" title="Chapter&#160;2.&#160;IRQ"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter&#160;1.&#160;Introduction</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="index.html">Prev</a>&#160;</td><th width="60%" align="center">&#160;</th><td width="20%" align="right">&#160;<a accesskey="n" href="irq.html">Next</a></td></tr></table><hr></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="intro"></a>Chapter&#160;1.&#160;Introduction</h1></div></div></div><p>
2     Tracepoints are static probe points that are located in strategic points
3     throughout the kernel. 'Probes' register/unregister with tracepoints
4     via a callback mechanism. The 'probes' are strictly typed functions that
5     are passed a unique set of parameters defined by each tracepoint.
6   </p><p>
7     From this simple callback mechanism, 'probes' can be used to profile, debug,
8     and understand kernel behavior. There are a number of tools that provide a
9     framework for using 'probes'. These tools include Systemtap, ftrace, and
10     LTTng.
11   </p><p>
12     Tracepoints are defined in a number of header files via various macros. Thus,
13     the purpose of this document is to provide a clear accounting of the available
14     tracepoints. The intention is to understand not only what tracepoints are
15     available but also to understand where future tracepoints might be added.
16   </p><p>
17     The API presented has functions of the form:
18     <code class="function">trace_tracepointname(function parameters)</code>. These are the
19     tracepoints callbacks that are found throughout the code. Registering and
20     unregistering probes with these callback sites is covered in the
21     <code class="filename">Documentation/trace/*</code> directory.
22   </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>&#160;</td><td width="20%" align="center">&#160;</td><td width="40%" align="right">&#160;<a accesskey="n" href="irq.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">The Linux Kernel Tracepoint API&#160;</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">&#160;Chapter&#160;2.&#160;IRQ</td></tr></table></div></body></html>
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