drivers/net: Correct redundant test
[linux-2.6/mini2440.git] / Documentation / DocBook / tracepoint.tmpl
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1 <?xml version="1.0" encoding="UTF-8"?>
2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
3 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
5 <book id="Tracepoints">
6 <bookinfo>
7 <title>The Linux Kernel Tracepoint API</title>
9 <authorgroup>
10 <author>
11 <firstname>Jason</firstname>
12 <surname>Baron</surname>
13 <affiliation>
14 <address>
15 <email>jbaron@redhat.com</email>
16 </address>
17 </affiliation>
18 </author>
19 </authorgroup>
21 <legalnotice>
22 <para>
23 This documentation is free software; you can redistribute
24 it and/or modify it under the terms of the GNU General Public
25 License as published by the Free Software Foundation; either
26 version 2 of the License, or (at your option) any later
27 version.
28 </para>
30 <para>
31 This program is distributed in the hope that it will be
32 useful, but WITHOUT ANY WARRANTY; without even the implied
33 warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
34 See the GNU General Public License for more details.
35 </para>
37 <para>
38 You should have received a copy of the GNU General Public
39 License along with this program; if not, write to the Free
40 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
41 MA 02111-1307 USA
42 </para>
44 <para>
45 For more details see the file COPYING in the source
46 distribution of Linux.
47 </para>
48 </legalnotice>
49 </bookinfo>
51 <toc></toc>
52 <chapter id="intro">
53 <title>Introduction</title>
54 <para>
55 Tracepoints are static probe points that are located in strategic points
56 throughout the kernel. 'Probes' register/unregister with tracepoints
57 via a callback mechanism. The 'probes' are strictly typed functions that
58 are passed a unique set of parameters defined by each tracepoint.
59 </para>
61 <para>
62 From this simple callback mechanism, 'probes' can be used to profile, debug,
63 and understand kernel behavior. There are a number of tools that provide a
64 framework for using 'probes'. These tools include Systemtap, ftrace, and
65 LTTng.
66 </para>
68 <para>
69 Tracepoints are defined in a number of header files via various macros. Thus,
70 the purpose of this document is to provide a clear accounting of the available
71 tracepoints. The intention is to understand not only what tracepoints are
72 available but also to understand where future tracepoints might be added.
73 </para>
75 <para>
76 The API presented has functions of the form:
77 <function>trace_tracepointname(function parameters)</function>. These are the
78 tracepoints callbacks that are found throughout the code. Registering and
79 unregistering probes with these callback sites is covered in the
80 <filename>Documentation/trace/*</filename> directory.
81 </para>
82 </chapter>
84 <chapter id="irq">
85 <title>IRQ</title>
86 !Iinclude/trace/events/irq.h
87 </chapter>
89 </book>