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" []>
4
5<book id="Tracepoints">
6 <bookinfo>
7  <title>The Linux Kernel Tracepoint API</title>
8
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   <author>
20    <firstname>William</firstname>
21    <surname>Cohen</surname>
22    <affiliation>
23     <address>
24      <email>wcohen@redhat.com</email>
25     </address>
26    </affiliation>
27   </author>
28  </authorgroup>
29
30  <legalnotice>
31   <para>
32     This documentation is free software; you can redistribute
33     it and/or modify it under the terms of the GNU General Public
34     License as published by the Free Software Foundation; either
35     version 2 of the License, or (at your option) any later
36     version.
37   </para>
38
39   <para>
40     This program is distributed in the hope that it will be
41     useful, but WITHOUT ANY WARRANTY; without even the implied
42     warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
43     See the GNU General Public License for more details.
44   </para>
45
46   <para>
47     You should have received a copy of the GNU General Public
48     License along with this program; if not, write to the Free
49     Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
50     MA 02111-1307 USA
51   </para>
52
53   <para>
54     For more details see the file COPYING in the source
55     distribution of Linux.
56   </para>
57  </legalnotice>
58 </bookinfo>
59
60 <toc></toc>
61  <chapter id="intro">
62   <title>Introduction</title>
63   <para>
64     Tracepoints are static probe points that are located in strategic points
65     throughout the kernel. 'Probes' register/unregister with tracepoints
66     via a callback mechanism. The 'probes' are strictly typed functions that
67     are passed a unique set of parameters defined by each tracepoint.
68   </para>
69
70   <para>
71     From this simple callback mechanism, 'probes' can be used to profile, debug,
72     and understand kernel behavior. There are a number of tools that provide a
73     framework for using 'probes'. These tools include Systemtap, ftrace, and
74     LTTng.
75   </para>
76
77   <para>
78     Tracepoints are defined in a number of header files via various macros. Thus,
79     the purpose of this document is to provide a clear accounting of the available
80     tracepoints. The intention is to understand not only what tracepoints are
81     available but also to understand where future tracepoints might be added.
82   </para>
83
84   <para>
85     The API presented has functions of the form:
86     <function>trace_tracepointname(function parameters)</function>. These are the
87     tracepoints callbacks that are found throughout the code. Registering and
88     unregistering probes with these callback sites is covered in the
89     <filename>Documentation/trace/*</filename> directory.
90   </para>
91  </chapter>
92
93  <chapter id="irq">
94   <title>IRQ</title>
95!Iinclude/trace/events/irq.h
96  </chapter>
97
98  <chapter id="signal">
99   <title>SIGNAL</title>
100!Iinclude/trace/events/signal.h
101  </chapter>
102
103  <chapter id="block">
104   <title>Block IO</title>
105!Iinclude/trace/events/block.h
106  </chapter>
107
108  <chapter id="workqueue">
109   <title>Workqueue</title>
110!Iinclude/trace/events/workqueue.h
111  </chapter>
112</book>
113