1 <!DOCTYPE html PUBLIC
"-//W3C//DTD HTML 4.01 Transitional//EN">
4 <title>Linux Trace Toolkit Next Generation User Documentation
</title>
8 <h1>Linux Trace Toolkit Next Generation User Documentation
</h1>
10 Author : Mathieu Desnoyers, September
2005<br>
11 Last update : January
21st,
2009<br>
12 (originally known as the LTTng QUICKSTART guide)
14 <h2>Table of Contents
</h2>
17 <li><a href=
"#intro" name=
"TOCintro">Introduction
</a></li>
18 <li><a href=
"#section1" name=
"TOCsection1">Installing LTTng and LTTV from
20 <li><a href=
"#userspacetracing" name=
"TOCuserspacetracing">Userspace Tracing
</ul>
22 <li><a href=
"#section2" name=
"TOCsection2">Using LTTng and LTTV
</a></li>
23 <li><a href=
"#section3" name=
"TOCsection3">Adding kernel and user-space
25 <li><a href=
"#section4" name=
"TOCsection4">Creating Debian and RPM packages
32 <h2><a href=
"#TOCintro" name=
"intro">Introduction
</a></h2>
34 This document is made of four parts : the first one explains how
35 to install LTTng and LTTV from sources, the second one describes the steps
36 to follow to trace a system and view it. The third part explains
37 briefly how to add a new trace point to the kernel and to user space
38 applications. The fourth and last part explains how to create Debian or RPM
39 packages from the LTTng and LTTV sources.
41 These operations are made for installing the LTTng
0.86 tracer on a linux
2.6.X
42 kernel. You will also find instructions for installation of LTTV
0.12.x : the
43 Linux Trace Toolkit Viewer.
44 To see the list of compatibilities between LTTng, ltt-control, LTTV, please
47 href=
"http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV versions compatibility
</a>
48 The lttng patch is necessary to have the tracing hooks in the kernel.
52 Supported architectures :
56 <li> PowerPC
32 and
64 bits
57 <li> ARM (with limited timestamping precision, e.g.
1HZ. Need
58 architecture-specific support for better precision)
64 <li> PowerPC
32 and
64 bits
65 <li> Possibly others. Takes care of endianness and type size difference between
66 the LTTng traces and the LTTV analysis tool.
71 <h2><a href=
"#TOCsection1" name=
"section1">Installation from sources
</a></h2>
74 <li>Prerequisites
</li>
77 Tools needed to follow the package download steps :
85 You have to install the standard development libraries and programs necessary
89 (from Documentation/Changes in the Linux kernel tree)
90 Gnu C
2.95.3 # gcc --version
91 Gnu make
3.79.1 # make --version
93 util-linux
2.10o # fdformat --version
94 module-init-tools
0.9.10 # depmod -V
98 You might also want to have libncurses5 to have the text mode kernel
99 configuration menu, but there are alternatives.
102 Prerequisites for LTTV
0.x.x installation are :
106 gtk
2.4 or better development libraries
107 (Debian : libgtk2.0, libgtk2.0-dev)
108 (Fedora : gtk2, gtk2-devel)
109 note : For Fedora users : this might require at least core
3 from Fedora,
110 or you might have to compile your own GTK2 library.
111 glib
2.4 or better development libraries
112 (Debian : libglib2.0-
0, libglib2.0-dev)
113 (Fedora : glib2, glib2-devel)
114 libpopt development libraries
115 (Debian : libpopt0, libpopt-dev)
117 libpango development libraries
118 (Debian : libpango1.0, libpango1.0-dev)
119 (Fedora : pango, pango-devel)
120 libc6 development librairies
121 (Debian : libc6, libc6-dev)
122 (Fedora : glibc, glibc)
129 See the list of compatibilities between LTTng, ltt-control and LTTV at :
131 href=
"http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV
132 versions compatibility
</a>.
135 <li>Getting the LTTng packages
</li>
141 (see http://ltt.polymtl.ca/lttng for package listing)
142 wget http://ltt.polymtl.ca/lttng/patch-
2.6.X-lttng-
0.x.xx.tar.bz2
143 bzip2 -cd patch-
2.6.X-lttng-
0.x.xx.tar.bz2 | tar xvof -
147 <li>Getting LTTng kernel sources
</li>
152 wget http://kernel.org/pub/linux/kernel/v2.6/linux-
2.6.X.tar.bz2
153 bzip2 -cd linux-
2.6.X.tar.bz2 | tar xvof -
155 - For LTTng
0.9.4- cat /usr/src/lttng/patch*-
2.6.X-lttng-
0.x.xx* | patch -p1
156 - For LTTng
0.9.5+ apply the patches in the order specified in the series file,
159 mv linux-
2.6.X linux-
2.6.X-lttng-
0.x.xx
163 <li>Installing a LTTng kernel
</li>
167 cd /usr/src/linux-
2.6.X-lttng-
0.x.xx
168 make menuconfig (or make xconfig or make config)
169 Select the < Help
> button if you are not familiar with kernel
171 Items preceded by [*] means they has to be built into the kernel.
172 Items preceded by [M] means they has to be built as modules.
173 Items preceded by [ ] means they should be removed.
174 go to the
"General setup" section
175 Select the following options :
176 [*] Prompt for development and/or incomplete code/drivers
178 [*] Activate userspace markers ABI (experimental, optional)
179 [*] Immediate value optimization (optional)
180 [*] Linux Trace Toolkit Next Generation (LTTng) --->
181 <M> or <*
> Compile lttng tracing probes
182 <M> or <*
> Linux Trace Toolkit High-speed Lockless Data Relay
183 <M> or <*
> Linux Trace Toolkit Lock-Protected Data Relay
184 <M> or <*
> Linux Trace Toolkit Serializer
185 <M> or <*
> Linux Trace Toolkit Marker Control
186 <M> or <*
> Linux Trace Toolkit Tracer
187 [*] Align Linux Trace Toolkit Traces
188 <M> or <*
> Support logging events from userspace
189 [*] Support trace extraction from crash dump
190 <M> or <*
> Linux Trace Toolkit Trace Controller
191 <M> or <*
> Linux Trace Toolkit State Dump
197 (if necessary, create a initrd with mkinitrd or your preferate alternative)
198 (mkinitrd -o /boot/initrd.img-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx)
203 Select the Linux
2.6.X-lttng-
0.x.xx kernel in your boot loader.
206 cp vmlinux.strip /boot/vmlinux-
2.6.X-lttng-
0.x.xx
207 cp System.map /boot/System.map-
2.6.X-lttng-
0.x.xx
208 cp .config /boot/config-
2.6.X-lttng-
0.x.xx
209 depmod -ae -F /boot/System.map-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx
210 mkinitrd /boot/initrd.img-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx
211 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
212 that comes first is the default kernel)
214 select the right entry at the yaboot prompt (see choices : tab, select : type
215 the kernel name followed by enter)
216 Select the Linux
2.6.X-lttng-
0.x.xx kernel in your boot loader.
220 <li>Editing the system wide configuration
</li>
223 You must activate debugfs and specify a mount point. This is typically done in
224 fstab such that it happens at boot time. If you have never used DebugFS before,
225 these operation would do this for you :
229 cp /etc/fstab /etc/fstab.lttng.bkp
230 echo
"debugfs /mnt/debugfs debugfs rw 0 0" >> /etc/fstab
234 then, rebooting or issuing the following command will activate debugfs :
240 You need to load the LTT modules to be able to control tracing from user
241 space. This is done by issuing the following commands. Note however
242 these commands load all LTT modules. Depending on what options you chose to
243 compile statically, you may not need to issue all these commands.
246 modprobe ltt-trace-control
247 modprobe ltt-marker-control
249 modprobe ltt-serialize
252 modprobe kernel-trace
258 modprobe syscall-trace
260 #if locking tracing is wanted, uncomment the following
261 #modprobe lockdep-trace
265 If you want to have complete information about the kernel state (including all
266 the process names), you need to load the ltt-statedump module. This is done by
267 issuing the command :
270 modprobe ltt-statedump
273 You can automate at boot time loading the ltt-control module by :
276 cp /etc/modules /etc/modules.bkp
277 echo ltt-trace-control
>> /etc/modules
278 echo ltt-marker-control
>> /etc/modules
279 echo ltt-tracer
>> /etc/modules
280 echo ltt-serialize
>> /etc/modules
281 echo ltt-relay
>> /etc/modules
282 echo ipc-trace
>> /etc/modules
283 echo kernel-trace
>> /etc/modules
284 echo mm-trace
>> /etc/modules
285 echo net-trace
>> /etc/modules
286 echo fs-trace
>> /etc/modules
287 echo jbd2-trace
>> /etc/modules
288 echo ext4-trace
>> /etc/modules
289 echo syscall-trace
>> /etc/modules
290 echo trap-trace
>> /etc/modules
291 #if locking tracing is wanted, uncomment the following
292 #echo lockdep-trace
>> /etc/modules
295 <li>Getting and installing the ltt-control package (on the traced machine)
</li>
297 (note : the ltt-control package contains lttd and lttctl. Although it has the
298 same name as the ltt-control kernel module, they are *not* the same thing.)
303 wget http://ltt.polymtl.ca/lttng/ltt-control-
0.x-xxxx2006.tar.gz
304 gzip -cd ltt-control-
0.x-xxxx2008.tar.gz | tar xvof -
305 cd ltt-control-
0.x-xxxx2006
306 (refer to README to see the development libraries that must be installed on you
313 <h3><a href=
"#TOCuserspacetracing" name=
"userspacetracing">Userspace tracing
</a></h3>
316 Make sure you selected the kernel menuconfig option :
317 <M> or <*
> Support logging events from userspace
318 And that the ltt-userspace-event kernel module is loaded if selected as a
321 Simple userspace tracing is available through
322 echo
"some text to record" > /mnt/debugfs/ltt/write_event
324 It will appear in the trace under event :
329 <li>Getting and installing the LTTV package (on the visualisation machine, same
330 or different from the visualisation machine)
</li>
335 wget http://ltt.polymtl.ca/packages/lttv-
0.x.xx-xxxx2008.tar.gz
336 gzip -cd lttv-
0.x.xx-xxxx2008.tar.gz | tar xvof -
337 cd lttv-
0.x.xx-xxxx2008
338 (refer to README to see the development libraries that must be installed on your
348 <h2><a href=
"#TOCsection2" name=
"section2">Using LTTng and LTTV
</a></h2>
350 <li>IMPORTANT : Arm Linux Kernel Markers after each boot
</li>
355 <li>Use graphical LTTV to control tracing and analyse traces
</li>
357 lttv-gui (or /usr/local/bin/lttv-gui)
358 - Spot the
"Tracing Control" icon : click on it
359 (it's a traffic light icon)
360 - enter the root password
364 * You should now see a trace
367 <li>Use text mode LTTng to control tracing
</li>
369 The tracing can be controlled from a terminal by using the lttctl command (as
374 lttctl -C -w /tmp/trace1 trace1
376 Stop tracing and destroy trace channels :
380 see lttctl --help for details.
383 (note : to see if the buffers has been filled, look at the dmesg output after
384 lttctl -R or after stopping tracing from the GUI, it will show an event lost
385 count. If it is the case, try using larger buffers. See lttctl --help to learn
386 how. lttv now also shows event lost messages in the console when loading a trace
387 with missing events or lost subbuffers.)
389 <li>Use text mode LTTV
</li>
391 Feel free to look in /usr/local/lib/lttv/plugins to see all the text and
392 graphical plugins available.
394 For example, a simple trace dump in text format is available with :
396 lttv -m textDump -t /tmp/trace
399 See lttv -m textDump --help for detailed command line options of textDump.
401 It is, in the current state of the project, very useful to use
"grep" on the
402 text output to filter by specific event fields. You can later copy the timestamp
403 of the events to the clipboard and paste them in the GUI by clicking on the
404 bottom right label
"Current time". Support for this type of filtering should
405 be added to the filter module soon.
409 Starting from LTTng
0.5.105 and ltt-control
0.20, a new mode can be used :
410 hybrid. It can be especially useful when studying big workloads on a long period
413 When using this mode, the most important, low rate control information will be
414 recorded during all the trace by lttd (i.e. process creation/exit). The high
415 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
416 flight recorder buffer (now named flight-channelname_X).
418 The following lttctl commands take an hybrid trace :
420 Create trace channel, start lttd on normal channels, start tracing:
422 lttctl -C -w /tmp/trace2 -o channel.kernel.overwrite=
1 trace2
425 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
427 lttctl -D -w /tmp/trace2 trace2
430 Each
"overwrite" channel is flight recorder channel.
432 <li>Flight recorder mode
</li>
434 The flight recorder mode writes data into overwritten buffers for all channels,
435 including control channels, except for the facilities tracefiles. It consists of
436 setting all channels to
"overwrite".
438 The following lttctl commands take a flight recorder trace :
440 lttctl -C -w /tmp/trace3 -o channel.all.overwrite=
1 trace3
442 lttctl -D -w /tmp/trace3 trace3
448 <h2><a href=
"#TOCsection3" name=
"section3">Adding new instrumentations with the
453 See Documentation/markers.txt and Documentation/tracepoints.txt in your kernel
456 <li>Add new events to userspace programs with
457 <a href=
"http://ltt.polymtl.ca/packages/">userspace markers packages
</a></li>
460 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
461 allows inserting markers in executables and libraries, currently only on x86_32
464 href=
"http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2">markers-userspace-
0.5.tar.bz2
</a> or more recent.
467 Note that a new design document for a
3rd generation of tracepoint/marker-based
468 userspace tracing is available at
<a
469 href=
"http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/ust.html">LTTng User-space Tracing
470 Design
"</a>. This new infrastructure is not yet implemented.
473 The easy quick-and-dirty way to perform userspace tracing is currently to write
474 an string to /mnt/debugfs/ltt/write_event. See <a
475 href="#userspacetracing
">Userspace tracing</a> in the
476 installation for sources section of this document.
480 <h2><a href="#TOCsection4
" name="section4
">Creating Debian or RPM packages</a></h2>
483 <li>Create custom LTTV Debian packages</li>
486 Use : dpkg-buildpackage -rfakeroot
489 You should then have your LTTV .deb files created for your architecture.
491 <li>Create custom LTTng packages</li>
493 For building LTTng Debian packages :
494 get the build tree with patches applies as explained in section 2.
497 make menuconfig (or xconfig or config) (customize your configuration)
498 make-kpkg kernel_image
501 You will then see your freshly created .deb in /usr/src. Install it with
503 dpkg -i /usr/src/(image-name).deb
506 Then, follow the section "Editing the system wide configuration
" in section 2.