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"-//W3C//DTD HTML 4.01 Transitional//EN">
4 <title>Linux Trace Toolkit Quickstart
</title>
8 <h1>Linux Trace Toolkit Quickstart
</h1>
10 Author : Mathieu Desnoyers, September
2005<br>
11 Last update : January
21st,
2009<br>
13 <h2>Table of Contents
</h2>
16 <li><a href=
"#intro" name=
"TOCintro">Introduction
</a></li>
17 <li><a href=
"#section1" name=
"TOCsection1">Installing LTTng and LTTV from
19 <li><a href=
"#section2" name=
"TOCsection2">Using LTTng and LTTV
</a></li>
20 <li><a href=
"#section3" name=
"TOCsection3">Adding kernel and user-space
22 <li><a href=
"#section4" name=
"TOCsection4">Creating Debian and RPM packages
29 <h2><a href=
"#TOCintro" name=
"intro">Introduction
</a></h2>
31 This document is made of four parts : the first one explains how
32 to install LTTng and LTTV from sources, the second one describes the steps
33 to follow to trace a system and view it. The third part explains
34 briefly how to add a new trace point to the kernel and to user space
35 applications. The fourth and last part explains how to create Debian or RPM
36 packages from the LTTng and LTTV sources.
38 These operations are made for installing the LTTng
0.86 tracer on a linux
2.6.X
39 kernel. You will also find instructions for installation of LTTV
0.12.x : the
40 Linux Trace Toolkit Viewer.
41 To see the list of compatibilities between LTTng, ltt-control, LTTV, please
44 href=
"http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV versions compatibility
</a>
45 The lttng patch is necessary to have the tracing hooks in the kernel.
49 Supported architectures :
53 <li> PowerPC
32 and
64 bits
54 <li> ARM (with limited timestamping precision, e.g.
1HZ. Need
55 architecture-specific support for better precision)
61 <li> PowerPC
32 and
64 bits
62 <li> Possibly others. Takes care of endianness and type size difference between
63 the LTTng traces and the LTTV analysis tool.
68 <h2><a href=
"#TOCsection2" name=
"section2">Installation from sources
</a></h2>
71 <li>Prerequisites
</li>
74 Tools needed to follow the package download steps :
82 You have to install the standard development libraries and programs necessary
86 (from Documentation/Changes in the Linux kernel tree)
87 Gnu C
2.95.3 # gcc --version
88 Gnu make
3.79.1 # make --version
90 util-linux
2.10o # fdformat --version
91 module-init-tools
0.9.10 # depmod -V
95 You might also want to have libncurses5 to have the text mode kernel
96 configuration menu, but there are alternatives.
99 Prerequisites for LTTV
0.x.x installation are :
103 gtk
2.4 or better development libraries
104 (Debian : libgtk2.0, libgtk2.0-dev)
105 (Fedora : gtk2, gtk2-devel)
106 note : For Fedora users : this might require at least core
3 from Fedora,
107 or you might have to compile your own GTK2 library.
108 glib
2.4 or better development libraries
109 (Debian : libglib2.0-
0, libglib2.0-dev)
110 (Fedora : glib2, glib2-devel)
111 libpopt development libraries
112 (Debian : libpopt0, libpopt-dev)
114 libpango development libraries
115 (Debian : libpango1.0, libpango1.0-dev)
116 (Fedora : pango, pango-devel)
117 libc6 development librairies
118 (Debian : libc6, libc6-dev)
119 (Fedora : glibc, glibc)
126 See the list of compatibilities between LTTng, ltt-control and LTTV at :
128 href=
"http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV
129 versions compatibility
</a>.
132 <li>Getting the LTTng packages
</li>
138 (see http://ltt.polymtl.ca/lttng for package listing)
139 wget http://ltt.polymtl.ca/lttng/patch-
2.6.X-lttng-
0.x.xx.tar.bz2
140 bzip2 -cd patch-
2.6.X-lttng-
0.x.xx.tar.bz2 | tar xvof -
144 <li>Getting LTTng kernel sources
</li>
149 wget http://kernel.org/pub/linux/kernel/v2.6/linux-
2.6.X.tar.bz2
150 bzip2 -cd linux-
2.6.X.tar.bz2 | tar xvof -
152 - For LTTng
0.9.4- cat /usr/src/lttng/patch*-
2.6.X-lttng-
0.x.xx* | patch -p1
153 - For LTTng
0.9.5+ apply the patches in the order specified in the series file,
156 mv linux-
2.6.X linux-
2.6.X-lttng-
0.x.xx
160 <li>Installing a LTTng kernel
</li>
164 cd /usr/src/linux-
2.6.X-lttng-
0.x.xx
165 make menuconfig (or make xconfig or make config)
166 Select the < Help
> button if you are not familiar with kernel
168 Items preceded by [*] means they has to be built into the kernel.
169 Items preceded by [M] means they has to be built as modules.
170 Items preceded by [ ] means they should be removed.
171 go to the
"General setup" section
172 Select the following options :
173 [*] Prompt for development and/or incomplete code/drivers
175 [*] Activate userspace markers ABI (experimental, optional)
176 [*] Immediate value optimization (optional)
177 [*] Linux Trace Toolkit Next Generation (LTTng) --->
178 <M> or <*
> Compile lttng tracing probes
179 <M> or <*
> Linux Trace Toolkit High-speed Lockless Data Relay
180 <M> or <*
> Linux Trace Toolkit Lock-Protected Data Relay
181 <M> or <*
> Linux Trace Toolkit Serializer
182 <M> or <*
> Linux Trace Toolkit Marker Control
183 <M> or <*
> Linux Trace Toolkit Tracer
184 [*] Align Linux Trace Toolkit Traces
185 <M> or <*
> Support logging events from userspace
186 [*] Support trace extraction from crash dump
187 <M> or <*
> Linux Trace Toolkit Trace Controller
188 <M> or <*
> Linux Trace Toolkit State Dump
194 (if necessary, create a initrd with mkinitrd or your preferate alternative)
195 (mkinitrd -o /boot/initrd.img-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx)
200 Select the Linux
2.6.X-lttng-
0.x.xx kernel in your boot loader.
203 cp vmlinux.strip /boot/vmlinux-
2.6.X-lttng-
0.x.xx
204 cp System.map /boot/System.map-
2.6.X-lttng-
0.x.xx
205 cp .config /boot/config-
2.6.X-lttng-
0.x.xx
206 depmod -ae -F /boot/System.map-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx
207 mkinitrd /boot/initrd.img-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx
208 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
209 that comes first is the default kernel)
211 select the right entry at the yaboot prompt (see choices : tab, select : type
212 the kernel name followed by enter)
213 Select the Linux
2.6.X-lttng-
0.x.xx kernel in your boot loader.
217 <li>Editing the system wide configuration
</li>
220 You must activate debugfs and specify a mount point. This is typically done in
221 fstab such that it happens at boot time. If you have never used DebugFS before,
222 these operation would do this for you :
226 cp /etc/fstab /etc/fstab.lttng.bkp
227 echo
"debugfs /mnt/debugfs debugfs rw 0 0" >> /etc/fstab
231 then, rebooting or issuing the following command will activate debugfs :
237 You need to load the LTT modules to be able to control tracing from user
238 space. This is done by issuing the following commands. Note however
239 these commands load all LTT modules. Depending on what options you chose to
240 compile statically, you may not need to issue all these commands.
243 modprobe ltt-trace-control
244 modprobe ltt-marker-control
246 modprobe ltt-serialize
249 modprobe kernel-trace
255 modprobe syscall-trace
257 #if locking tracing is wanted, uncomment the following
258 #modprobe lockdep-trace
262 If you want to have complete information about the kernel state (including all
263 the process names), you need to load the ltt-statedump module. This is done by
264 issuing the command :
267 modprobe ltt-statedump
270 You can automate at boot time loading the ltt-control module by :
273 cp /etc/modules /etc/modules.bkp
274 echo ltt-trace-control
>> /etc/modules
275 echo ltt-marker-control
>> /etc/modules
276 echo ltt-tracer
>> /etc/modules
277 echo ltt-serialize
>> /etc/modules
278 echo ltt-relay
>> /etc/modules
279 echo ipc-trace
>> /etc/modules
280 echo kernel-trace
>> /etc/modules
281 echo mm-trace
>> /etc/modules
282 echo net-trace
>> /etc/modules
283 echo fs-trace
>> /etc/modules
284 echo jbd2-trace
>> /etc/modules
285 echo ext4-trace
>> /etc/modules
286 echo syscall-trace
>> /etc/modules
287 echo trap-trace
>> /etc/modules
288 #if locking tracing is wanted, uncomment the following
289 #echo lockdep-trace
>> /etc/modules
292 <li>Getting and installing the ltt-control package (on the traced machine)
</li>
294 (note : the ltt-control package contains lttd and lttctl. Although it has the
295 same name as the ltt-control kernel module, they are *not* the same thing.)
300 wget http://ltt.polymtl.ca/lttng/ltt-control-
0.x-xxxx2006.tar.gz
301 gzip -cd ltt-control-
0.x-xxxx2008.tar.gz | tar xvof -
302 cd ltt-control-
0.x-xxxx2006
303 (refer to README to see the development libraries that must be installed on you
310 <li>Userspace tracing
</li>
313 Make sure you selected the kernel menuconfig option :
314 <M> or <*
> Support logging events from userspace
315 And that the ltt-userspace-event kernel module is loaded if selected as a
318 Simple userspace tracing is available through
319 echo
"some text to record" > /mnt/debugfs/ltt/write_event
321 It will appear in the trace under event :
326 <li>Getting and installing the LTTV package (on the visualisation machine, same
327 or different from the visualisation machine)
</li>
332 wget http://ltt.polymtl.ca/packages/lttv-
0.x.xx-xxxx2008.tar.gz
333 gzip -cd lttv-
0.x.xx-xxxx2008.tar.gz | tar xvof -
334 cd lttv-
0.x.xx-xxxx2008
335 (refer to README to see the development libraries that must be installed on your
342 <li>Getting and installing the markers-userspace package for user space
343 tracing (experimental)
</li>
346 href=
"http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2">markers-userspace-
0.5.tar.bz2
</a> or more recent.
351 <h2><a href=
"#TOCsection3" name=
"section3">Using LTTng and LTTV
</a></h2>
353 <li>IMPORTANT : Arm Linux Kernel Markers after each boot
</li>
358 <li>Use graphical LTTV to control tracing and analyse traces
</li>
360 lttv-gui (or /usr/local/bin/lttv-gui)
361 - Spot the
"Tracing Control" icon : click on it
362 (it's a traffic light icon)
363 - enter the root password
367 * You should now see a trace
370 <li>Use text mode LTTng to control tracing
</li>
372 The tracing can be controlled from a terminal by using the lttctl command (as
377 lttctl -C -w /tmp/trace1 trace1
379 Stop tracing and destroy trace channels :
383 see lttctl --help for details.
386 (note : to see if the buffers has been filled, look at the dmesg output after
387 lttctl -R or after stopping tracing from the GUI, it will show an event lost
388 count. If it is the case, try using larger buffers. See lttctl --help to learn
389 how. lttv now also shows event lost messages in the console when loading a trace
390 with missing events or lost subbuffers.)
392 <li>Use text mode LTTV
</li>
394 Feel free to look in /usr/local/lib/lttv/plugins to see all the text and
395 graphical plugins available.
397 For example, a simple trace dump in text format is available with :
399 lttv -m textDump -t /tmp/trace
402 See lttv -m textDump --help for detailed command line options of textDump.
404 It is, in the current state of the project, very useful to use
"grep" on the
405 text output to filter by specific event fields. You can later copy the timestamp
406 of the events to the clipboard and paste them in the GUI by clicking on the
407 bottom right label
"Current time". Support for this type of filtering should
408 be added to the filter module soon.
412 Starting from LTTng
0.5.105 and ltt-control
0.20, a new mode can be used :
413 hybrid. It can be especially useful when studying big workloads on a long period
416 When using this mode, the most important, low rate control information will be
417 recorded during all the trace by lttd (i.e. process creation/exit). The high
418 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
419 flight recorder buffer (now named flight-channelname_X).
421 The following lttctl commands take an hybrid trace :
423 Create trace channel, start lttd on normal channels, start tracing:
425 lttctl -C -w /tmp/trace2 -o channel.kernel.overwrite=
1 trace2
428 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
430 lttctl -D -w /tmp/trace2 trace2
433 Each
"overwrite" channel is flight recorder channel.
435 <li>Flight recorder mode
</li>
437 The flight recorder mode writes data into overwritten buffers for all channels,
438 including control channels, except for the facilities tracefiles. It consists of
439 setting all channels to
"overwrite".
441 The following lttctl commands take a flight recorder trace :
443 lttctl -C -w /tmp/trace3 -o channel.all.overwrite=
1 trace3
445 lttctl -D -w /tmp/trace3 trace3
448 **************************************************************
449 ** Section
4 * Adding new instrumentations with the markers **
450 **************************************************************
452 See Documentation/markers.txt and Documentation/tracepoints.txt in your kernel
455 * Add new events to userspace programs with userspace markers
456 http://ltt.polymtl.ca/packages/
458 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
459 allows inserting markers in executables and libraries, currently only on x86_32
462 ***********************************************************
463 ** Section
5 * Creating Debian or RPM packages **
464 ***********************************************************
466 * Create custom LTTV Debian packages
468 Use : dpkg-buildpackage -rfakeroot
470 You should then have your LTTV .deb files created for your architecture.
472 * Create custom LTTng packages
474 For building LTTng Debian packages :
476 Get the build tree with patches applies as explained in section
2.
478 make menuconfig (or xconfig or config) (customize your configuration)
479 make-kpkg kernel_image
481 You will then see your freshly created .deb in /usr/src. Install it with
482 dpkg -i /usr/src/(image-name).deb
484 Then, follow the section
"Editing the system wide configuration" in section
2.