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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
<book id="TapsetRef">
<bookinfo>
<title>SystemTap Tapset Reference Manual</title>
<authorgroup>
<author>
<firstname>William</firstname>
<surname>Cohen</surname>
<affiliation>
<address>
<email>wcohen@redhat.com</email>
</address>
</affiliation>
</author>
</authorgroup>
<copyright>
<year>2008, 2009</year>
<holder>Red Hat, Inc.</holder>
</copyright>
<legalnotice>
<para>
This documentation is free software; you can redistribute
it and/or modify it under the terms of the GNU General Public
License version 2 as published by the Free Software Foundation.
</para>
<para>
This program is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
</para>
<para>
You should have received a copy of the GNU General Public
License along with this program; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
MA 02111-1307 USA
</para>
<para>
For more details see the file COPYING in the source
distribution of Linux.
</para>
</legalnotice>
</bookinfo>
<toc></toc>
<chapter id="introduction">
<title>Introduction</title>
<para>
SystemTap provides free software (GPL) infrastructure to simplify the
gathering of information about the running Linux system. This assists
diagnosis of a performance or functional problem. SystemTap eliminates the
need for the developer to go through the tedious and disruptive instrument,
recompile, install, and reboot sequence that may be otherwise required to
collect data.
</para>
<para>
SystemTap provides a simple command line interface and scripting language
for writing instrumentation for a live running kernel. The instrumentation
makes extensive use of the probe points and functions provided in the
<firstterm>tapset</firstterm> library. This document describes the various
probe points and functions.
</para>
<section id="format">
<title>Tapset Name Format</title>
<para>In this guide, tapset definitions appear in the following format:</para>
<screen>
name:return (parameters)
definition
</screen>
<para>
The <replaceable>return</replaceable> field specifies what data type the
tapset extracts and returns from the kernel during a probe (and thus,
returns). Tapsets use 2 data types for
<replaceable>return</replaceable>: <literal>long</literal> (tapset
extracts and returns an integer) and <literal>string</literal> (tapset
extracts and returns a string).
</para>
<para>
In some cases, tapsets do not have a <replaceable>return</replaceable>
value. This simply means that the tapset does not extract anything from
the kernel. This is common among asynchronous events such as timers,
exit functions, and print functions.
</para>
<!--
<varlistentry>
<term></term>
<listitem>
<para></para>
</listitem>
</varlistentry>
-->
</section>
</chapter>
<chapter id="context_stp">
<title>Context Functions</title>
<para>
The context functions provide additional information about the where
the event occurred.
These functions can provide information such as a backtrace
where the event occured
and the current register values for the processor.
</para>
!Itapset/context.stp
!Itapset/context-symbols.stp
!Itapset/context-unwind.stp
</chapter>
<chapter id="timestamp_stp">
<title>Timestamp Functions</title>
<para>
Each timestamp function returns a value to indicate when
the function is executed.
Thus, these returned values can be used to indicate
when an event occurs, provide an ordering for events, or compute
the amount of time elapsed between to time stamps.
</para>
!Itapset/timestamp.stp
</chapter>
<chapter id="memory_stp">
<title>Memory Tapset</title>
!Itapset/memory.stp
</chapter>
<chapter id="iosched.stp">
<title>IO Scheduler Tapset</title>
<para>
This family of probe points is used to probe the IO scheduler activities.
It contains the following probe points:
</para>
!Itapset/ioscheduler.stp
</chapter>
<chapter id="scsi.stp">
<title>SCSI Tapset</title>
<para>
This family of probe points is used to probe the SCSI activities.
It contains the following probe points:
</para>
!Itapset/scsi.stp
</chapter>
<chapter id="networking.stp">
<title>Networking Tapset</title>
<para>
This family of probe points is used to probe the activities of
network device.
</para>
!Itapset/networking.stp
</chapter>
<chapter id="socket.stp">
<title>Socket Tapset</title>
<para>
This family of probe points is used to probe socket activities.
It contains the following probe points:
</para>
!Itapset/socket.stp
</chapter>
<chapter id="tcp.stp">
<title>TCP Tapset</title>
<para>
This family of probe points is used to probe TCP layer activities.
It contains the following probe points:
</para>
!Itapset/tcp.stp
</chapter>
<chapter id="upd.stp">
<title>UDP Tapset</title>
<para>
This family of probe points is used to probe UDP layer activities.
It contains the following probe points:
</para>
!Itapset/udp.stp
</chapter>
<chapter id="process.stp">
<title>Process Tapset</title>
<para>
This family of probe points is used to probe the process activities.
It contains the following probe points:
</para>
!Itapset/process.stp
</chapter>
<chapter id="signal.stp">
<title>Signal Tapset</title>
<para>
This family of probe points is used to probe signal activities.
It contains the following probe points:
</para>
!Itapset/signal.stp
</chapter>
</book>
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