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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
                      "/usr/share/sgml/docbook/dtd/4.3/xdocbook.dtd">
<!--<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" >-->

<book>

<bookinfo>
<title>Linux Trace Toolkit Viewer User Guide</title>
<authorgroup>
<author>
<firstname>Mathieu</firstname>
<surname>Desnoyers</surname>
</author>
</authorgroup>

<date>11/01/2006</date>
<releaseinfo>1.00.02</releaseinfo>

<abstract>
<para>
This document describes how to install <application>Linux Trace
Toolkit Viewer</application> and how to use it.

</para>
</abstract>

<keywordset>
<keyword>Linux Trace Toolkit Viewer</keyword>
<keyword>Linux Trace Toolkit</keyword>
<keyword>tracing</keyword>
<keyword>Linux</keyword>
<keyword>visualization</keyword>
<keyword>operating system</keyword>
</keywordset>

</bookinfo>

<chapter>
<title>Introduction</title>
<para>
Linux Trace Toolkit (LTT) is a tracing tool that permits to get all the possible
execution information from the Linux Kernel. It is based on kernel
instrumentation and a high-speed relay file system to copy the information from
the kernel space to the user space.
</para>

<para>
Linux Trace Toolkit Viewer (LTTV) is the second generation of visualization
tool. It is based on a trace format (the files where the data is recorded on
disk) written by the LTTng tracer.
</para>

<para>
This document explains all the steps that are necessary in order to record a
trace with LTT and view it with LTTV.
</para>
</chapter>

<chapter>
<title>Getting started</title>

<sect1 id="install">
<title>Installing LTTng and LTTV</title>
<para>
Follow the QUICKSTART guide found at
<ulink url="http://ltt.polymtl.ca">ltt.polymtl.ca</ulink>.
</para>

<!--
<title>Installing LTTV</title>
<para>
First, you must download the latests version of LTTV. You should get it from
this site : <ulink url="http://ltt.polymtl.ca">ltt.polymtl.ca</ulink>.
I suggest that you get it from the "Packages" section.
</para>

<para>
You need a recent gcc compiler to compile the project. You might want to use gcc
3.2 or newer.
You will also need some libraries in order to compile it. They are described in
the README of the LTTV package. These are GTK 2.0, GLIB 2.0, "popt" and Pango 1.0.
Install them if they are not on your system. Remember that if you use a package
manager from you favourite Linux distribution, you will need to specifically
install the librairies'development packages.
</para>


<para>
Then, you are ready to compile LTTV. Extract and untar the file you previously
downloaded : 
</para>

<screen>
<prompt>$</prompt> <userinput>tar -xvzof LinuxTraceToolkitViewer-x.x-dddddddd.tar.bz2</userinput>
</screen>

<para>
Then, go to the directory newly created, and type :
</para>

<screen>
<prompt>$</prompt> <userinput>./configure</userinput>
<prompt>$</prompt> <userinput>make</userinput>
<prompt>#</prompt> <userinput>make install</userinput> (as root)
</screen>
-->
<para>
At this point, LTTV is installed in the default directory. You may find the
lttv executable in /usr/local/bin and the librairies in /usr/local/lib. You will
also notice the presence of the convert executable in /usr/local/bin. This tool
will be used later to convert from the Linux Trace Toolkit trace format to the
LTTV format.
</para>
<!--
<para>
You are now ready to go to the next step : installing the LTT kernel tracer.
</para>


</sect1>



<sect1 id="install-tracer">
<title>Installing LTT kernel tracer</title>
<para>
The goal of this guide is not to describe the Linux Trace Toolkit project in
details, as it is a
seperate project for now. It just gives pointers to the basic steps you must
take in order to generate a trace suitable for conversion.
</para>

<para>
First, go to the <ulink url="http://ltt.polymtl.ca">ltt.polymtl.ca</ulink>
website, in the "Patches for the Official LTT" section. Use the latest version
of patches available. The file name convention used goes like this : 
aaaaaa-x.x\-\-bbbbb-y.y.patch. That means a patch made for aaaaa, release x.x,
that adds bbbbb, release y.y to it. Notice the presence of the \-\- sign that
separates the "from" field from the name of the patch applied. This way, it's
impossible to be mixed up on the specific sequence of patch application. I
suggest that you use the "relayfs", "ltt" and then "md" patches. The "md" patch
adds events useful to LTTV that are not in the official LTT.
</para>

<para>
Once you have the patches you need, get the matching Linux kernel version, apply
the patches on it, configure it, install it, reboot with the new kernel. You then
have an instrumented kernel ready for tracing. If you have problems during this phase,
please refer to <ulink
url="http://www.opersys.com/ltt">www.opersys.com/ltt</ulink>. If you need
instructions about how to recompile a kernel, see
<ulink url="http://www.tldp.org/HOWTO/Kernel-HOWTO/">Kernel-HOWTO</ulink>.
</para>

</sect1>

<sect1 id="install-daemon">
<title>Installing LTT trace recording daemon</title>
<para>
In order to install the LTT trace recording daemon, you should get the latest
TraceToolkit (or ltt) package from the LTT ftp site.
Use the link "Official Linux Trace Toolkit Packages" on the
<ulink url="http://ltt.polymtl.ca">ltt.polymtl.ca</ulink> webpage to access it.
As of November 30, 2004, the most recent version is 0.9.6-pre3.
</para>
<para>
Then, you should apply the TraceToolkit patches from the LTTV website related
to the package version. Get them from the "Patches for the Official LTT"
section.
</para>
<para>
You are now ready to install the daemon in your system. Please refer to the
documentation in the package for details.
</para>
<para>
You may now use the following command to record a sample 30 seconds trace in
your current directory. Command line switches are described on the official
LTT website.
</para>
<screen>
<prompt>#</prompt><userinput>tracedaemon -ts30 sample.out sample.proc (as root) userinput></userinput>
</screen>
</sect1>



<sect1 id="convert">
<title>Conversion from LTT to LTTV trace format</title>
<para>
If you used the default directory for installation, you should find the
conversion tool in /usr/local/bin/convert. Before using it, some other files are
necessary. You will find them in
/usr/local/share/LinuxTraceToolkitViewer/convert/. Those are sysInfo and
core.xml.
</para>
<para>
sysInfo is a script that get informations about the traced computer. It should
be invoked like this :
</para>
<screen>
<prompt>$</prompt> <userinput>sh /usr/local/LinuxTraceToolkitViewer/convert/sysInfo</userinput>
</screen>
<para>
It creates a file named sysInfo.out. This file has to be present in the current
directory where the convert tool will be executed. I suggest that you choose a
destination directory where will be written converted traces right now, put sysInfo.out in it, at
use it as current directory for running the convert tool.
</para>
<para>
Once the sysInfo.out file is ready and you have a trace ready for conversion,
you should invoke convert like the following example. This is for a uniprocessor
computer. If you whish to get detailed explanation on the parameters, simply
execute the convert tool without any option. You may also wish to see the
/usr/local/LinuxTraceToolkitViewer/convert/README file.
</para>
<screen>
<prompt>$</prompt> <userinput>/usr/local/bin/convert sample.proc 1 sample.trace sample.converted</userinput>
</screen>
<para>
You must then copy the core event definition file to the converted trace directory :
</para>
<screen>
<prompt>$</prompt> <userinput>cp /usr/local/share/LinuxTraceToolkitViewer/convert/core.xml sample.converted/</userinput>
</screen>
<para>
You now have a converted trace ready for visualization in LTTV. Congratulations!
</para>
-->
</sect1>

<sect1 id="running">
<title>Running the executable with basic libraries</title>
<para>
Starting the graphical mode with the basic viewer activated is as simple as :
</para>
<screen>
<prompt>$</prompt> <userinput>lttv-gui</userinput>
</screen>
<para>
Using the text mode is very simple too. Look in /usr/local/lib/lttv/plugins for
the list of modules. You may use the --help switch to get basic help on the
command line parameters of every loaded modules. To simply output the events of
a trace in a text file, try the textDump module. The batchAnalysis module
permits to do batch mode analysis (state and statistics calculation ) on a
trace.
</para>
<screen>
<prompt>$</prompt> <userinput>lttv -L /usr/local/lib/lttv/plugins -m textDump --help</userinput>
</screen>
</sect1>
</chapter>

<chapter>
<title>Using LTTV graphical interface</title>

<sect1 id="mainwindow">
<title>LTTV main window</title>
<para>
This section describes the main functionnalities that are provided by the LTTV
GUI and how to use them.
</para>
<para>
By default, when the lttv GUI starts with all the graphical modules loaded,
it loads the statistics viewer, the control flow viewer, and the detailed event
list inside a tab. Other viewers can be added later to this tab by interacting
with the main window. Let's describe the operations available on the window :
</para>
<screenshot>
<mediaobject>
<imageobject>
<imagedata srccredit="Mathieu Desnoyers, 2004" fileref="lttv-numbered-5.png"
format="PNG" align="center"/>
</imageobject>
<imageobject>
<imagedata srccredit="Mathieu Desnoyers, 2004"
fileref="lttv-numbered-5.eps"
format="EPS" align="center"/>
</imageobject>
<!--<imagedata srccredit="Mathieu Desnoyers, 2004" fileref="lttv-numbered-6.svg"
format="SVG" align="center" scalefit="1"/>
</imageobject>-->
<caption><para>Linux Trace Toolkit Viewer GUI</para></caption>
</mediaobject>
</screenshot>
<orderedlist>
<listitem>
<para>
This toolbar allows you to navigate through the basic functionnalities of LTTV.
The first button opens a new window and the second one, a new tab. You can leave
your mouse over the buttons to read the information provided by the tooltips.
</para>
</listitem>
<listitem>
<para>
This notebook, containing different tabs, lets you select the "Trace Set" you
want to interact with. A trace set is an aggregation of traces, synchronised in
time. You may also want to use one tab per viewer by simply cloning the traceset
to a new tab. This way, you can have vertically stacked viewers in one tab, as
well as different viewers, independant from the time interval. Note that once
the Trace Set cloning is done, each trace set becomes completely independant.
For Traceset cloning, see the File Menu.
</para>
</listitem>
<listitem>
<para>
These buttons let you control the computation in progress on a trace. As
sometimes the computation may last for a while, you may want to stop it, restart
it from the beginning or simply to continue from where you stopped. This is
exactly what those three buttons offer you.
</para>
</listitem>
<listitem>
<para>
Buttons on the right side of the last spacer are semantically different from the
others. While the other buttons at the left side of the bar are built in the
lttv program and let you operate the basic functionnalities, the buttons at the
right side let you add a viewer to the active Tab. They belong to the
viewers themselves. The number of buttons that appears there should directly
depend on the number of viewer's modules loaded.
</para>
</listitem>
<listitem>
<para>
This is a tree representing the multiple statistics available for the current
traceset. This is shown by the guistatistics viewer.
</para>
</listitem>
<listitem>
<para>
This is the Y axis of the guicontrolflow viewer. It shows the process list of
the traced system. You may notice that it grows : it dynamically adds
process when they appear in the trace.
</para>
</listitem>
<listitem>
<para>
This is a (missing) time bar for the X axis. Maybe will it be used for viewer
specific buttons eventually. Work in progress.
</para>
</listitem>
<listitem>
<para>
The is the current time selected. The concept of current event and current time
selected is synchronised in a Tab for all the viewers. The control flow viewer
shows it a vertical white dotted line. You move this marker by clicking on the
background of the process state graph. This graph shows evolution of each
process's state through time. The meaning of the colors will be explained later.
</para>
</listitem>
<listitem>
<para>
This is the details event list. It shown the detailed information about each
event of the trace. It is synchronised with the current time and current event,
so selecting an event changes other viewer's current time and reciprocally.
</para>
</listitem>
<listitem>
<para>
You can enter the values of start time and end time you wish to see on the
screen here. It also supports pasting time as text input, simply by clicking of
the "Time Frame", "start" or "end:" fields. A valid entry consists of any
digital input separated by any quantity of non digital characters. For example :
"I start at 356247.124626 and stop at 724524.453455" would be a valid input
for the "Time Frame" field.
</para>
</listitem>
<listitem>
<para>
This horizontal scrollbar modifies the window of time shown by all the viewers
in the tab. It is linked with the fields below it (described at number 10 and
12). Another way to modify the time shown is to use the zoom buttons of the
toolbar (yes, the ones that looks like magnifying glasses).
</para>
</listitem>
<listitem>
<para>
This field works just like the "Time Frame" field. It modifies the current time
selected by the viewers. For example, changing its value will change the current
event selected by the detailed events list and the current time selected by the
control flow viewer.
</para>
</listitem>
</orderedlist>
</sect1>

<sect1 id="ControlFlowColors">
<title>Control Flow View Colors</title>
<screenshot>
<mediaobject>
<imageobject>
<imagedata srccredit="Mathieu Desnoyers, 2004" fileref="lttv-color-list.png"
format="PNG" align="center"/>
</imageobject>
<imageobject>
<imagedata srccredit="Mathieu Desnoyers, 2004"
fileref="lttv-color-list.eps"
format="EPS" align="center"/>
</imageobject>
<!--<imagedata srccredit="Mathieu Desnoyers, 2004" fileref="lttv-numbered-6.svg"
format="SVG" align="center" scalefit="1"/>
</imageobject>-->
<caption><para>Control Flow View Color Legend</para></caption>
</mediaobject>
</screenshot>

<para>
Here is a description of the colors used in the control flow view. Each color
represents a state of the process at a given time.
</para>

<itemizedlist>
<listitem>
<para>
White : this color is used for process from which state is not known. It may
happen when you seek quickly at a far time in the trace just after it has been
launched. At that moment, the precomputed state information is incomplete. The
"unknown" state is used to identify this. Note that the viewer gets refreshed
once the precomputation ends.
</para>
</listitem>
<listitem>
<para>
Green : This color is only used for process when they are running in user mode.
That includes execution of all the source code of an executable as well as the
libraries it uses.
</para>
</listitem>
<listitem>
<para>
Pale blue : A process is doing a system call to the kernel, and the mode is
switched from process limited rights to super user mode. Only code from the
kernel (including modules) should be run in that state.
</para>
</listitem>
<listitem>
<para>
Yellow : The kernel is running a trap that services a fault. The most frequent
trap is the memory page fault trap : it is called every time a page is missing
from physical memory.
</para>
</listitem>
<listitem>
<para>
Orange : IRQ servicing routine is running. It interrupts the currently running
process. As the IRQ does not change the currently running process (on some
architectures it uses the same stack as the process), the IRQ state is shown in
the state of the process. IRQ can be nested : a higher priority interrupt can
interrupt a lower priority interrupt.
</para>
</listitem>
<listitem>
<para>
Pink : SoftIRQ handler is running. A SoftIRQ is normally triggered by an
interrupt that whishes to have some work done very soon, but not "now". This is
especially useful, for example, to have the longest part of the network stack
traversal done : a too long computation in the interrupt handler would increase
the latency of the system. Therefore, doing the long part of the computation in
a softirq that will be run just after the IRQ handler exits will permits to do
this work while interrupts are enabled, without increasing the system latency.
</para>
</listitem>
<listitem>
<para>
Dark red : A process in that state is waiting for an input/output operation to
complete before it can continue its execution.
</para>
</listitem>
<listitem>
<para>
Dark yellow : A process is ready to run, but waiting to get the CPU (a schedule
in event).
</para>
</listitem>
<listitem>
<para>
Dark purple : A process in zombie state. This state happens when a process
exits and then waits for the parent to wait for it (wait() or waitpid()).
</para>
</listitem>
<listitem>
<para>
Dark green : A process has just been created by its parent and is waiting for
first scheduling.
</para>
</listitem>
<listitem>
<para>
Magenta : The process has exited, but still has the control of the CPU. It may
happend if it has some tasks to do in the exit system call.
</para>
</listitem>
</itemizedlist>
</sect1>
</chapter>

<chapter>
<title>Using LTTV text modules</title>
<sect1 id="batchAnalysis">
<title>The batch analysis module</title>
<para>
This batch analysis module can be invoked like this :
</para>
<screen>
<prompt>$</prompt> <userinput>lttv -L path/to/lib/plugins -m batchAnalysis\
-t trace1 -t trace2 ...</userinput>
</screen>
<para>
It permits to call any registered action to perform in batch mode on all the
trace set, which consists of the traces loaded on the command line. Actions that
are built in the batchAnalysis module are statistics computation. They can be
triggered by using the -s (--stats) switch.
</para>
<para>
However, the batchAnalysis module is mostly a backend for every other text
module that does batch computation over a complete trace set.
</para>
</sect1>
<sect1 id="textDump">
<title>The text dump module</title>
<para>
 The goal of this module is to convert the binary data of the traces into
a formatted text file.
</para>
<para>
The text dump module is a good example of a usage of the batch analysis module
backend. In fact, the text dump module depends on it. You don't need to
explicitly load the batchAnalysis module though, as lttv offers a rich module
backend that deals with the dependencies, loading the module automatically if
needed.
</para>
<para>
The text dump module is invoked just like the batchAnalysis module. It adds more
options that can be specified in argument. You may specify the -o switch for the
output file name of the text dump. You can enable the output of the field names
(the identifier of the fields) with the -l switch. The -s switch, for process
states, is very useful to indicate the state in which the process is when the
event happens.
</para>
<para>
If you use the --help option on the textDump module, you will see all the detail
about the switches that can be used to show per cpu statistics and per process
statistics. You will notice that you can use both the switches for the
batchAnalysis module and those for textDump. You will also notice that the
options --process_state (from textDump) and --stats (from batchAnalysis) has the
same short name "-s". If you choose to invoke this option using the short name,
it will use the option of the last module loaded just before the -s switch.
</para>
<para>
For exemple, if you load the textDump module with -m textDump, it will first
load the batchAnalysis module, and then load itself. As it is the last module
loaded, the -s switch used after it will signify --process_stats. On the other
hand, if you choose to specify explicitly the loading of both modules like this
:
</para>
<screen>
<prompt>$</prompt> <userinput>lttv -L path/to/lib/plugins -m batchAnalysis -s\
-m textDump -s -t trace</userinput>
</screen>
<para>
The first "-s" will invoke batchAnalysis --stats and the second "-s" will invoke
textDump --process_state. The list of options generated by --help follows the
order of registration of the options by the modules, therefore the invocation 
order of the modules.
</para>
</sect1>

</chapter>


</book>