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QUICKSTART

How to use LTTng and LTTV in a few lines :

This document is made of four parts : The first one explains how to install
LTTng and LTTV from Debian and RPM binary packages, the second one explains how
to install LTTng and LTTV from sources and the third one describes the steps
to follow to trace a system and view it. The fourth and last part explains
briefly how to add a new trace point to the kernel.

What you will typically want is to read sections 1 and 3 : install LTTng from
binary packages and use it. If there are no packages ready for your system, you
will have to install from sources (section 2) instead.

These operations are made for installing the LTTng 0.4 tracer on a
linux 2.6.12-rc4-mm2 kernel. You will also find instructions for installtion of
LTTV 0.6.x : the Linux Trace Toolkit Viewer.

At this point, the -mm tree of the kernel is used because it has RelayFS support
in it. In a nearby future, a vanilla kernel 2.6.14 will be used, as RelayFS has
been integrated in the linux 2.6.14-rc series.

The following lttng patch is necessary to have the tracing hooks in the kernel.
The following ltt-control module controls the tracing.

Required programs and librairies are assumed to be automatically installed in an
installation with Debian or RPM packages. In the case of an installation from
sources, the dependencies are listed.


Author : Mathieu Desnoyers, September 2005



***********************************************************
** Section 1 * Installation from Debian or RPM packages  **
***********************************************************

No Debian or RPM packages are ready yet.

TODO


***********************************************************
** Section 2 * Installation from sources                 **
***********************************************************

* Prerequisites

Tools needed to follow the package download steps :

o wget
o bzip2
o gzip
o tar

You have to install the standard development librairies and programs necessary
to compile a kernel :

(from Documentation/Changes in the Linux kernel tree)
o  Gnu C                  2.95.3                  # gcc --version
o  Gnu make               3.79.1                  # make --version
o  binutils               2.12                    # ld -v
o  util-linux             2.10o                   # fdformat --version
o  module-init-tools      0.9.10                  # depmod -V

You might also want to have libncurses5 to have the text mode kernel
configuration menu, but there are alternatives.

Prerequisites for LTTV 0.6.x installation are :

gtk 2.4 or better development libraries (libgtk2.0, libgtk2.0-dev)
glib 2.4 or better development libraries (libglib2.0-0, libglib2.0-dev)
libpopt development libraries (libpopt0, libpopt-dev)
libpango development libraries (libpango1.0, libpango1.0-dev)
libc6 development librairies (libc6, libc6-dev)


* Getting the LTTng packages

su -
mkdir /usr/src/lttng
cd /usr/src/lttng
(see http://ltt.polymtl.ca/lttng for package listing)
wget http://ltt.polymtl.ca/lttng/lttng-modules-0.3.tar.bz2
wget http://ltt.polymtl.ca/lttng/patch-2.6.12-rc4-mm2-lttng-0.4.bz2
bzip2 -cd lttng-modules-0.3.tar.bz2 | tar xvof -


* Getting LTTng kernel sources

su -
cd /usr/src
wget http://kernel.org/pub/linux/kernel/v2.6/testing/linux-2.6.12-rc4.tar.bz2
wget http://kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.12-rc4/2.6.12-rc4-mm2/2.6.12-rc4-mm2.bz2
bzip2 -cd linux-2.6.12-rc4.tar.bz2 | tar xvof -
cd linux-2.6.12-rc4
bzip2 -cd ../2.6.12-rc4-mm2.bz2 | patch -p1
bzip2 -cd /usr/src/lttng/patch-2.6.12-rc4-mm2-lttng-0.4.bz2 | patch -p1
cd ..
mv linux-2.6.12-rc4 linux-2.6.12-rc4-mm2-lttng-0.4


* Installing a LTTng kernel

su -
cd /usr/src/linux-2.6.12-rc4-mm2-lttng-0.4
make menuconfig (or make xconfig or make config)
    Select the < Help > button if you are not familiar with kernel
    configuration.
    Items preceded by [*] means they has to be built into the kernel.
    Items preceded by [M] means they has to be built as modules.
    Items preceded by [ ] means they should be removed.
  go to the "General setup" section
    Select the following options :
    [*] Linux Trace Toolkit Instrumentation Support
    [M] or [*] Linux Trace Toolkit Tracer
        It makes no difference for the rest of the procedure whether the Tracer
        is compiled built-in or as a module.
    do NOT activate (not ready yet) :
       [ ] Align Linux Trace Toolkit Traces
       [ ] Activate Linux Trace Toolkit Heartbeat Timer
              IMPORTANT : This is enabled by default : you must disable it!
    Select <Exit>
  Select <Exit>
  Select <Yes>
make
make modules_install
make install

You must activate relayfs and specify a mount point. This is typically done in
fstab such that it happens at boot time.

If you have never used RelayFS before, these operation would do this for you :

mkdir /mnt/relayfs
cp /etc/fstab /etc/fstab.lttng.bkp
echo "relayfs         /mnt/relayfs    relayfs rw              0       0"  >> /etc/fstab

reboot

  Select the Linux 2.6.12-rc4-mm2-lttng-0.4 kernel in your boot loader.


* Install the ltt-modules

su -
cd /usr/src/lttng/lttng-modules-0.3
KERNELDIR=/usr/src/linux-2.6.12-rc4-mm2-lttng-0.4 make
KERNELDIR=/usr/src/linux-2.6.12-rc4-mm2-lttng-0.4 make modules_install

You need to load the ltt-control module to be able to control tracing from user
space. This is done by issuing the command :

modprobe ltt-control

You can automate at boot time loading the ltt-control module by :

echo ltt-control >> /etc/modules


* Getting and installing the LTTV package

su -
cd /usr/src
wget http://ltt.polymtl.ca/packages/LinuxTraceToolkitViewer-0.6.5-21092005.tar.gz
gzip -cd LinuxTraceToolkitViewer-0.6.5-21092005.tar.gz | tar xvof -
cd LinuxTraceToolkitViewer-0.6.5-21092005
(refer to README to see the development libraries that must be installed on you
system)
./configure
make
make install




***********************************************************
** Section 3 * Using LTTng and LTTV                      **
***********************************************************

* Use graphical LTTV to control tracing and analyse traces

lttv-gui (or /usr/local/bin/lttv-gui)
  - Spot the "Tracing Control" icon : click on it
      (it's a traffic light icon)
    - enter the root password
    - click "start"
    - click "stop"
    - Yes
      * You should now see a trace

* Use text mode LTTng to control tracing

The tracing can be controlled from a terminal by using the lttctl command (as
root).

Start tracing :

lttctl -n trace -d -l /mnt/relayfs/ltt -t /tmp/trace

Stop tracing and destroy trace channels :

lttctl -n trace -R

see lttctl --help for details.


* Use text mode LTTV

Fell free to look in /usr/local/lib/lttv/plugins to see all the text and
graphical plugins available.

For example, a simple trace dump in text format is available with :

lttv -m textDump -t /tmp/trace

see lttv -m textDump --help for detailed command line options of textDump.




***********************************************************
** Section 4 * Adding new instrumentations with genevent **
***********************************************************

* Getting and installing genevent

su -
cd /usr/src
wget http://ltt.polymtl.ca/packages/genevent-0.2.tar.gz
gzip -cd genevent-0.2.tar.gz | tar xvof -
cd genevent-0.2
make
make install


* Add new events to the kernel with genevent

su -
cd /usr/local/share/LinuxTraceToolkitViewer/facilities
cp process.xml yourfacility.xml
  * edit yourfacility.xml to fit your needs.
cd /tmp
/usr/local/bin/genevent /usr/local/share/LinuxTraceToolkitViewer/yourfacility.xml
cp ltt-facility-yourfacility.h ltt-facility-id-yourfacility.h \
         /usr/src/linux-2.6.12-rc4-mm2-lttng-0.4/include/linux/ltt
cp ltt-facility-loader-yourfacility.c ltt-facility-loader-yourfacility.h \
         /usr/src/linux-2.6.12-rc4-mm2-lttng-0.4/ltt
  * edit the kernel file you want to instrument
    - Add #include <linux/ltt/ltt-facility-yourfacility.h> at the beginning
      of the file.
    - Add a call to the tracing functions. See their names and parameters in
      /usr/src/linux-2.6.12-rc4-mm2-lttng-0.4/include/linux/ltt/ltt-facility-yourfacility.h