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
21 <li><a href=
"#prerequisites" name=
"TOCprerequisites">Prerequisistes
</li>
22 <li><a href=
"#getlttng" name=
"TOCgetlttng">Getting the LTTng packages
</li>
23 <li><a href=
"#getlttngsrc" name=
"TOCgetlttngsrc">Getting the LTTng kernel sources
</li>
24 <li><a href=
"#installlttng" name=
"TOCinstalllttng">Installing a LTTng kernel
</li>
25 <li><a href=
"#editconfig" name=
"TOCeditconfig">Editing the system wide
27 <li><a href=
"#getlttctl" name=
"TOCgetlttctl">Getting and installing the
28 ltt-control package
</li>
29 <li><a href=
"#userspacetracing" name=
"TOCuserspacetracing">Userspace Tracing
</li>
30 <li><a href=
"#getlttv" name=
"TOCgetlttv">Getting and installing the LTTV package
</ul>
31 <li><a href=
"#section2" name=
"TOCsection2">Using LTTng and LTTV
</a></li>
32 <li><a href=
"#section3" name=
"TOCsection3">Adding kernel and user-space
35 <li><a href=
"#kerneltp" name=
"TOCkerneltp">Adding kernel instrumentation
</a></li>
36 <li><a href=
"#usertp" name=
"TOCusertp">Adding userspace instrumentation
</a></li>
39 <li><a href=
"#section4" name=
"TOCsection4">Creating Debian and RPM packages
46 <h2><a href=
"#TOCintro" name=
"intro">Introduction
</a></h2>
48 This document is made of four parts : the first one explains how
49 to install LTTng and LTTV from sources, the second one describes the steps
50 to follow to trace a system and view it. The third part explains
51 briefly how to add a new trace point to the kernel and to user space
52 applications. The fourth and last part explains how to create Debian or RPM
53 packages from the LTTng and LTTV sources.
55 These operations are made for installing the LTTng
0.86 tracer on a linux
2.6.X
56 kernel. You will also find instructions for installation of LTTV
0.12.x : the
57 Linux Trace Toolkit Viewer.
58 To see the list of compatibilities between LTTng, ltt-control, LTTV, please
61 href=
"http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV versions compatibility
</a>
62 The lttng patch is necessary to have the tracing hooks in the kernel.
66 Supported architectures :
70 <li> PowerPC
32 and
64 bits
71 <li> ARM (with limited timestamping precision, e.g.
1HZ. Need
72 architecture-specific support for better precision)
78 <li> PowerPC
32 and
64 bits
79 <li> Possibly others. Takes care of endianness and type size difference between
80 the LTTng traces and the LTTV analysis tool.
85 <h2><a href=
"#TOCsection1" name=
"section1">Installation from sources
</a></h2>
88 <h3><a href=
"#TOCprerequisites" name=
"prerequisites">Prerequisites
</a></h3>
91 Tools needed to follow the package download steps :
99 You have to install the standard development libraries and programs necessary
100 to compile a kernel :
103 (from Documentation/Changes in the Linux kernel tree)
104 Gnu C
2.95.3 # gcc --version
105 Gnu make
3.79.1 # make --version
106 binutils
2.12 # ld -v
107 util-linux
2.10o # fdformat --version
108 module-init-tools
0.9.10 # depmod -V
112 You might also want to have libncurses5 to have the text mode kernel
113 configuration menu, but there are alternatives.
116 Prerequisites for LTTV
0.x.x installation are :
120 gtk
2.4 or better development libraries
121 (Debian : libgtk2.0, libgtk2.0-dev)
122 (Fedora : gtk2, gtk2-devel)
123 note : For Fedora users : this might require at least core
3 from Fedora,
124 or you might have to compile your own GTK2 library.
125 glib
2.4 or better development libraries
126 (Debian : libglib2.0-
0, libglib2.0-dev)
127 (Fedora : glib2, glib2-devel)
128 libpopt development libraries
129 (Debian : libpopt0, libpopt-dev)
131 libpango development libraries
132 (Debian : libpango1.0, libpango1.0-dev)
133 (Fedora : pango, pango-devel)
134 libc6 development librairies
135 (Debian : libc6, libc6-dev)
136 (Fedora : glibc, glibc)
143 See the list of compatibilities between LTTng, ltt-control and LTTV at :
145 href=
"http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV
146 versions compatibility
</a>.
149 <h3><a href=
"#TOCgetlttng" name=
"getlttng">Getting the LTTng packages
</a></h3>
155 (see http://ltt.polymtl.ca/lttng for package listing)
156 wget http://ltt.polymtl.ca/lttng/patch-
2.6.X-lttng-
0.x.xx.tar.bz2
157 bzip2 -cd patch-
2.6.X-lttng-
0.x.xx.tar.bz2 | tar xvof -
161 <h3><a href=
"#TOCgetlttngsrc" name=
"getlttngsrc">Getting LTTng kernel sources
</a></h3>
166 wget http://kernel.org/pub/linux/kernel/v2.6/linux-
2.6.X.tar.bz2
167 bzip2 -cd linux-
2.6.X.tar.bz2 | tar xvof -
169 - For LTTng
0.9.4- cat /usr/src/lttng/patch*-
2.6.X-lttng-
0.x.xx* | patch -p1
170 - For LTTng
0.9.5+ apply the patches in the order specified in the series file,
173 mv linux-
2.6.X linux-
2.6.X-lttng-
0.x.xx
177 <h3><a href=
"#TOCinstalllttng" name=
"installlttng">Installing a LTTng kernel
</a></h3>
181 cd /usr/src/linux-
2.6.X-lttng-
0.x.xx
182 make menuconfig (or make xconfig or make config)
183 Select the < Help
> button if you are not familiar with kernel
185 Items preceded by [*] means they has to be built into the kernel.
186 Items preceded by [M] means they has to be built as modules.
187 Items preceded by [ ] means they should be removed.
188 go to the
"General setup" section
189 Select the following options :
190 [*] Prompt for development and/or incomplete code/drivers
192 [*] Activate userspace markers ABI (experimental, optional)
193 [*] Immediate value optimization (optional)
194 [*] Linux Trace Toolkit Next Generation (LTTng) --->
195 <M> or <*
> Compile lttng tracing probes
196 <M> or <*
> Linux Trace Toolkit High-speed Lockless Data Relay
197 <M> or <*
> Linux Trace Toolkit Lock-Protected Data Relay
198 <M> or <*
> Linux Trace Toolkit Serializer
199 <M> or <*
> Linux Trace Toolkit Marker Control
200 <M> or <*
> Linux Trace Toolkit Tracer
201 [*] Align Linux Trace Toolkit Traces
202 <M> or <*
> Support logging events from userspace
203 [*] Support trace extraction from crash dump
204 <M> or <*
> Linux Trace Toolkit Trace Controller
205 <M> or <*
> Linux Trace Toolkit State Dump
211 (if necessary, create a initrd with mkinitrd or your preferate alternative)
212 (mkinitrd -o /boot/initrd.img-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx)
217 Select the Linux
2.6.X-lttng-
0.x.xx kernel in your boot loader.
220 cp vmlinux.strip /boot/vmlinux-
2.6.X-lttng-
0.x.xx
221 cp System.map /boot/System.map-
2.6.X-lttng-
0.x.xx
222 cp .config /boot/config-
2.6.X-lttng-
0.x.xx
223 depmod -ae -F /boot/System.map-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx
224 mkinitrd /boot/initrd.img-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx
225 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
226 that comes first is the default kernel)
228 select the right entry at the yaboot prompt (see choices : tab, select : type
229 the kernel name followed by enter)
230 Select the Linux
2.6.X-lttng-
0.x.xx kernel in your boot loader.
234 <h3><a href=
"#TOCeditconfig" name=
"editconfig">Editing the system wide
235 configuration
</a></h3>
238 You must activate debugfs and specify a mount point. This is typically done in
239 fstab such that it happens at boot time. If you have never used DebugFS before,
240 these operation would do this for you :
244 cp /etc/fstab /etc/fstab.lttng.bkp
245 echo
"debugfs /mnt/debugfs debugfs rw 0 0" >> /etc/fstab
249 then, rebooting or issuing the following command will activate debugfs :
255 You need to load the LTT modules to be able to control tracing from user
256 space. This is done by issuing the following commands. Note however
257 these commands load all LTT modules. Depending on what options you chose to
258 compile statically, you may not need to issue all these commands.
261 modprobe ltt-trace-control
262 modprobe ltt-marker-control
264 modprobe ltt-serialize
267 modprobe kernel-trace
273 modprobe syscall-trace
275 #if locking tracing is wanted, uncomment the following
276 #modprobe lockdep-trace
280 If you want to have complete information about the kernel state (including all
281 the process names), you need to load the ltt-statedump module. This is done by
282 issuing the command :
285 modprobe ltt-statedump
288 You can automate at boot time loading the ltt-control module by :
291 cp /etc/modules /etc/modules.bkp
292 echo ltt-trace-control
>> /etc/modules
293 echo ltt-marker-control
>> /etc/modules
294 echo ltt-tracer
>> /etc/modules
295 echo ltt-serialize
>> /etc/modules
296 echo ltt-relay
>> /etc/modules
297 echo ipc-trace
>> /etc/modules
298 echo kernel-trace
>> /etc/modules
299 echo mm-trace
>> /etc/modules
300 echo net-trace
>> /etc/modules
301 echo fs-trace
>> /etc/modules
302 echo jbd2-trace
>> /etc/modules
303 echo ext4-trace
>> /etc/modules
304 echo syscall-trace
>> /etc/modules
305 echo trap-trace
>> /etc/modules
306 #if locking tracing is wanted, uncomment the following
307 #echo lockdep-trace
>> /etc/modules
311 <h3><a href=
"#TOCgetlttctl" name=
"getlttctl">Getting and installing the
312 ltt-control package (on the traced machine)
</a></h3>
314 (note : the ltt-control package contains lttd and lttctl. Although it has the
315 same name as the ltt-control kernel module, they are *not* the same thing.)
320 wget http://ltt.polymtl.ca/lttng/ltt-control-
0.x-xxxx2006.tar.gz
321 gzip -cd ltt-control-
0.x-xxxx2008.tar.gz | tar xvof -
322 cd ltt-control-
0.x-xxxx2006
323 (refer to README to see the development libraries that must be installed on you
330 <h3><a href=
"#TOCuserspacetracing" name=
"userspacetracing">Userspace tracing
</a></h3>
333 Make sure you selected the kernel menuconfig option :
334 <M> or <*
> Support logging events from userspace
335 And that the ltt-userspace-event kernel module is loaded if selected as a
338 Simple userspace tracing is available through
339 echo
"some text to record" > /mnt/debugfs/ltt/write_event
341 It will appear in the trace under event :
346 <h3><a href=
"#TOCgetlttv" name=
"getlttv">Getting and installing the LTTV package
347 (on the visualisation machine, same
348 or different from the visualisation machine)
</a></h3>
353 wget http://ltt.polymtl.ca/packages/lttv-
0.x.xx-xxxx2008.tar.gz
354 gzip -cd lttv-
0.x.xx-xxxx2008.tar.gz | tar xvof -
355 cd lttv-
0.x.xx-xxxx2008
356 (refer to README to see the development libraries that must be installed on your
366 <h2><a href=
"#TOCsection2" name=
"section2">Using LTTng and LTTV
</a></h2>
368 <li>IMPORTANT : Arm Linux Kernel Markers after each boot
</li>
373 <li>Use graphical LTTV to control tracing and analyse traces
</li>
375 lttv-gui (or /usr/local/bin/lttv-gui)
376 - Spot the
"Tracing Control" icon : click on it
377 (it's a traffic light icon)
378 - enter the root password
382 * You should now see a trace
385 <li>Use text mode LTTng to control tracing
</li>
387 The tracing can be controlled from a terminal by using the lttctl command (as
392 lttctl -C -w /tmp/trace1 trace1
394 Stop tracing and destroy trace channels :
398 see lttctl --help for details.
401 (note : to see if the buffers has been filled, look at the dmesg output after
402 lttctl -R or after stopping tracing from the GUI, it will show an event lost
403 count. If it is the case, try using larger buffers. See lttctl --help to learn
404 how. lttv now also shows event lost messages in the console when loading a trace
405 with missing events or lost subbuffers.)
407 <li>Use text mode LTTV
</li>
409 Feel free to look in /usr/local/lib/lttv/plugins to see all the text and
410 graphical plugins available.
412 For example, a simple trace dump in text format is available with :
414 lttv -m textDump -t /tmp/trace
417 See lttv -m textDump --help for detailed command line options of textDump.
419 It is, in the current state of the project, very useful to use
"grep" on the
420 text output to filter by specific event fields. You can later copy the timestamp
421 of the events to the clipboard and paste them in the GUI by clicking on the
422 bottom right label
"Current time". Support for this type of filtering should
423 be added to the filter module soon.
427 Starting from LTTng
0.5.105 and ltt-control
0.20, a new mode can be used :
428 hybrid. It can be especially useful when studying big workloads on a long period
431 When using this mode, the most important, low rate control information will be
432 recorded during all the trace by lttd (i.e. process creation/exit). The high
433 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
434 flight recorder buffer (now named flight-channelname_X).
436 The following lttctl commands take an hybrid trace :
438 Create trace channel, start lttd on normal channels, start tracing:
440 lttctl -C -w /tmp/trace2 -o channel.kernel.overwrite=
1 trace2
443 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
445 lttctl -D -w /tmp/trace2 trace2
448 Each
"overwrite" channel is flight recorder channel.
450 <li>Flight recorder mode
</li>
452 The flight recorder mode writes data into overwritten buffers for all channels,
453 including control channels, except for the facilities tracefiles. It consists of
454 setting all channels to
"overwrite".
456 The following lttctl commands take a flight recorder trace :
458 lttctl -C -w /tmp/trace3 -o channel.all.overwrite=
1 trace3
460 lttctl -D -w /tmp/trace3 trace3
466 <h2><a href=
"#TOCsection3" name=
"section3">Adding new instrumentations with the
470 <h3><a href=
"#TOCkerneltp" name=
"kerneltp">Adding kernel
471 instrumentation
</a></h3>
475 href=
"http://git.kernel.org/?p=linux/kernel/git/compudj/linux-2.6-lttng.git;a=blob;f=Documentation/markers.txt">Documentation/markers.txt
</a>
477 href=
"http://git.kernel.org/?p=linux/kernel/git/compudj/linux-2.6-lttng.git;a=blob;f=Documentation/tracepoints.txt">Documentation/tracepoints.txt
</a> in your kernel
481 href=
"http://git.kernel.org/?p=linux/kernel/git/compudj/linux-2.6-lttng.git;a=tree;f=ltt/probes">ltt/probes/
</a>
482 for LTTng probe examples.
484 <h3><a href=
"#TOCusertp" name=
"usertp">Adding userspace instrumentation
</a></h3>
486 <li>Add new events to userspace programs with
487 <a href=
"http://ltt.polymtl.ca/packages/">userspace markers packages
</a></li>
490 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
491 allows inserting markers in executables and libraries, currently only on x86_32
494 href=
"http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2">markers-userspace-
0.5.tar.bz2
</a> or more recent.
497 Note that a new design document for a
3rd generation of tracepoint/marker-based
498 userspace tracing is available at
<a
499 href=
"http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/ust.html">LTTng User-space Tracing
500 Design
"</a>. This new infrastructure is not yet implemented.
503 The easy quick-and-dirty way to perform userspace tracing is currently to write
504 an string to /mnt/debugfs/ltt/write_event. See <a
505 href="#userspacetracing
">Userspace tracing</a> in the
506 installation for sources section of this document.
510 <h2><a href="#TOCsection4
" name="section4
">Creating Debian or RPM packages</a></h2>
513 <li>Create custom LTTV Debian packages</li>
516 Use : dpkg-buildpackage -rfakeroot
519 You should then have your LTTV .deb files created for your architecture.
521 <li>Create custom LTTng packages</li>
523 For building LTTng Debian packages :
524 get the build tree with patches applies as explained in section 2.
527 make menuconfig (or xconfig or config) (customize your configuration)
528 make-kpkg kernel_image
531 You will then see your freshly created .deb in /usr/src. Install it with
533 dpkg -i /usr/src/(image-name).deb
536 Then, follow the section "Editing the system wide configuration
" in section 2.