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>
38 <li><a href=
"#section4" name=
"TOCsection4">Creating Debian and RPM packages
41 <li><a href=
"#pkgdebian" name=
"TOCpkgdebian">Create custom LTTV Debian
42 <li><a href=
"#pkglttng" name=
"TOCpkglttng">Create custom LTTng packages
</a></li>
50 <h2><a href=
"#TOCintro" name=
"intro">Introduction
</a></h2>
52 This document is made of four parts : the first one explains how
53 to install LTTng and LTTV from sources, the second one describes the steps
54 to follow to trace a system and view it. The third part explains
55 briefly how to add a new trace point to the kernel and to user space
56 applications. The fourth and last part explains how to create Debian or RPM
57 packages from the LTTng and LTTV sources.
59 These operations are made for installing the LTTng
0.86 tracer on a linux
2.6.X
60 kernel. You will also find instructions for installation of LTTV
0.12.x : the
61 Linux Trace Toolkit Viewer.
62 To see the list of compatibilities between LTTng, ltt-control, LTTV, please
65 href=
"http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV versions compatibility
</a>
66 The lttng patch is necessary to have the tracing hooks in the kernel.
70 Supported architectures :
74 <li> PowerPC
32 and
64 bits
75 <li> ARM (with limited timestamping precision, e.g.
1HZ. Need
76 architecture-specific support for better precision)
82 <li> PowerPC
32 and
64 bits
83 <li> Possibly others. Takes care of endianness and type size difference between
84 the LTTng traces and the LTTV analysis tool.
89 <h2><a href=
"#TOCsection1" name=
"section1">Installation from sources
</a></h2>
92 <h3><a href=
"#TOCprerequisites" name=
"prerequisites">Prerequisites
</a></h3>
95 Tools needed to follow the package download steps :
103 You have to install the standard development libraries and programs necessary
104 to compile a kernel :
107 (from Documentation/Changes in the Linux kernel tree)
108 Gnu C
2.95.3 # gcc --version
109 Gnu make
3.79.1 # make --version
110 binutils
2.12 # ld -v
111 util-linux
2.10o # fdformat --version
112 module-init-tools
0.9.10 # depmod -V
116 You might also want to have libncurses5 to have the text mode kernel
117 configuration menu, but there are alternatives.
120 Prerequisites for LTTV
0.x.x installation are :
124 gtk
2.4 or better development libraries
125 (Debian : libgtk2.0, libgtk2.0-dev)
126 (Fedora : gtk2, gtk2-devel)
127 note : For Fedora users : this might require at least core
3 from Fedora,
128 or you might have to compile your own GTK2 library.
129 glib
2.4 or better development libraries
130 (Debian : libglib2.0-
0, libglib2.0-dev)
131 (Fedora : glib2, glib2-devel)
132 libpopt development libraries
133 (Debian : libpopt0, libpopt-dev)
135 libpango development libraries
136 (Debian : libpango1.0, libpango1.0-dev)
137 (Fedora : pango, pango-devel)
138 libc6 development librairies
139 (Debian : libc6, libc6-dev)
140 (Fedora : glibc, glibc)
147 See the list of compatibilities between LTTng, ltt-control and LTTV at :
149 href=
"http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV
150 versions compatibility
</a>.
153 <h3><a href=
"#TOCgetlttng" name=
"getlttng">Getting the LTTng packages
</a></h3>
159 (see http://ltt.polymtl.ca/lttng for package listing)
160 wget http://ltt.polymtl.ca/lttng/patch-
2.6.X-lttng-
0.x.xx.tar.bz2
161 bzip2 -cd patch-
2.6.X-lttng-
0.x.xx.tar.bz2 | tar xvof -
165 <h3><a href=
"#TOCgetlttngsrc" name=
"getlttngsrc">Getting LTTng kernel sources
</a></h3>
170 wget http://kernel.org/pub/linux/kernel/v2.6/linux-
2.6.X.tar.bz2
171 bzip2 -cd linux-
2.6.X.tar.bz2 | tar xvof -
173 - For LTTng
0.9.4- cat /usr/src/lttng/patch*-
2.6.X-lttng-
0.x.xx* | patch -p1
174 - For LTTng
0.9.5+ apply the patches in the order specified in the series file,
177 mv linux-
2.6.X linux-
2.6.X-lttng-
0.x.xx
181 <h3><a href=
"#TOCinstalllttng" name=
"installlttng">Installing a LTTng kernel
</a></h3>
185 cd /usr/src/linux-
2.6.X-lttng-
0.x.xx
186 make menuconfig (or make xconfig or make config)
187 Select the < Help
> button if you are not familiar with kernel
189 Items preceded by [*] means they has to be built into the kernel.
190 Items preceded by [M] means they has to be built as modules.
191 Items preceded by [ ] means they should be removed.
192 go to the
"General setup" section
193 Select the following options :
194 [*] Prompt for development and/or incomplete code/drivers
196 [*] Activate userspace markers ABI (experimental, optional)
197 [*] Immediate value optimization (optional)
198 [*] Linux Trace Toolkit Next Generation (LTTng) --->
199 <M> or <*
> Compile lttng tracing probes
200 <M> or <*
> Linux Trace Toolkit High-speed Lockless Data Relay
201 <M> or <*
> Linux Trace Toolkit Lock-Protected Data Relay
202 <M> or <*
> Linux Trace Toolkit Serializer
203 <M> or <*
> Linux Trace Toolkit Marker Control
204 <M> or <*
> Linux Trace Toolkit Tracer
205 [*] Align Linux Trace Toolkit Traces
206 <M> or <*
> Support logging events from userspace
207 [*] Support trace extraction from crash dump
208 <M> or <*
> Linux Trace Toolkit Trace Controller
209 <M> or <*
> Linux Trace Toolkit State Dump
215 (if necessary, create a initrd with mkinitrd or your preferate alternative)
216 (mkinitrd -o /boot/initrd.img-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx)
221 Select the Linux
2.6.X-lttng-
0.x.xx kernel in your boot loader.
224 cp vmlinux.strip /boot/vmlinux-
2.6.X-lttng-
0.x.xx
225 cp System.map /boot/System.map-
2.6.X-lttng-
0.x.xx
226 cp .config /boot/config-
2.6.X-lttng-
0.x.xx
227 depmod -ae -F /boot/System.map-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx
228 mkinitrd /boot/initrd.img-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx
229 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
230 that comes first is the default kernel)
232 select the right entry at the yaboot prompt (see choices : tab, select : type
233 the kernel name followed by enter)
234 Select the Linux
2.6.X-lttng-
0.x.xx kernel in your boot loader.
238 <h3><a href=
"#TOCeditconfig" name=
"editconfig">Editing the system wide
239 configuration
</a></h3>
242 You must activate debugfs and specify a mount point. This is typically done in
243 fstab such that it happens at boot time. If you have never used DebugFS before,
244 these operation would do this for you :
248 cp /etc/fstab /etc/fstab.lttng.bkp
249 echo
"debugfs /mnt/debugfs debugfs rw 0 0" >> /etc/fstab
253 then, rebooting or issuing the following command will activate debugfs :
259 You need to load the LTT modules to be able to control tracing from user
260 space. This is done by issuing the following commands. Note however
261 these commands load all LTT modules. Depending on what options you chose to
262 compile statically, you may not need to issue all these commands.
265 modprobe ltt-trace-control
266 modprobe ltt-marker-control
268 modprobe ltt-serialize
271 modprobe kernel-trace
277 modprobe syscall-trace
279 #if locking tracing is wanted, uncomment the following
280 #modprobe lockdep-trace
284 If you want to have complete information about the kernel state (including all
285 the process names), you need to load the ltt-statedump module. This is done by
286 issuing the command :
289 modprobe ltt-statedump
292 You can automate at boot time loading the ltt-control module by :
295 cp /etc/modules /etc/modules.bkp
296 echo ltt-trace-control
>> /etc/modules
297 echo ltt-marker-control
>> /etc/modules
298 echo ltt-tracer
>> /etc/modules
299 echo ltt-serialize
>> /etc/modules
300 echo ltt-relay
>> /etc/modules
301 echo ipc-trace
>> /etc/modules
302 echo kernel-trace
>> /etc/modules
303 echo mm-trace
>> /etc/modules
304 echo net-trace
>> /etc/modules
305 echo fs-trace
>> /etc/modules
306 echo jbd2-trace
>> /etc/modules
307 echo ext4-trace
>> /etc/modules
308 echo syscall-trace
>> /etc/modules
309 echo trap-trace
>> /etc/modules
310 #if locking tracing is wanted, uncomment the following
311 #echo lockdep-trace
>> /etc/modules
315 <h3><a href=
"#TOCgetlttctl" name=
"getlttctl">Getting and installing the
316 ltt-control package (on the traced machine)
</a></h3>
318 (note : the ltt-control package contains lttd and lttctl. Although it has the
319 same name as the ltt-control kernel module, they are *not* the same thing.)
324 wget http://ltt.polymtl.ca/lttng/ltt-control-
0.x-xxxx2006.tar.gz
325 gzip -cd ltt-control-
0.x-xxxx2008.tar.gz | tar xvof -
326 cd ltt-control-
0.x-xxxx2006
327 (refer to README to see the development libraries that must be installed on you
334 <h3><a href=
"#TOCuserspacetracing" name=
"userspacetracing">Userspace tracing
</a></h3>
337 Make sure you selected the kernel menuconfig option :
338 <M> or <*
> Support logging events from userspace
339 And that the ltt-userspace-event kernel module is loaded if selected as a
342 Simple userspace tracing is available through
343 echo
"some text to record" > /mnt/debugfs/ltt/write_event
345 It will appear in the trace under event :
350 <h3><a href=
"#TOCgetlttv" name=
"getlttv">Getting and installing the LTTV package
351 (on the visualisation machine, same
352 or different from the visualisation machine)
</a></h3>
357 wget http://ltt.polymtl.ca/packages/lttv-
0.x.xx-xxxx2008.tar.gz
358 gzip -cd lttv-
0.x.xx-xxxx2008.tar.gz | tar xvof -
359 cd lttv-
0.x.xx-xxxx2008
360 (refer to README to see the development libraries that must be installed on your
370 <h2><a href=
"#TOCsection2" name=
"section2">Using LTTng and LTTV
</a></h2>
372 <li>IMPORTANT : Arm Linux Kernel Markers after each boot
</li>
377 <li>Use graphical LTTV to control tracing and analyse traces
</li>
379 lttv-gui (or /usr/local/bin/lttv-gui)
380 - Spot the
"Tracing Control" icon : click on it
381 (it's a traffic light icon)
382 - enter the root password
386 * You should now see a trace
389 <li>Use text mode LTTng to control tracing
</li>
391 The tracing can be controlled from a terminal by using the lttctl command (as
396 lttctl -C -w /tmp/trace1 trace1
398 Stop tracing and destroy trace channels :
402 see lttctl --help for details.
405 (note : to see if the buffers has been filled, look at the dmesg output after
406 lttctl -R or after stopping tracing from the GUI, it will show an event lost
407 count. If it is the case, try using larger buffers. See lttctl --help to learn
408 how. lttv now also shows event lost messages in the console when loading a trace
409 with missing events or lost subbuffers.)
411 <li>Use text mode LTTV
</li>
413 Feel free to look in /usr/local/lib/lttv/plugins to see all the text and
414 graphical plugins available.
416 For example, a simple trace dump in text format is available with :
418 lttv -m textDump -t /tmp/trace
421 See lttv -m textDump --help for detailed command line options of textDump.
423 It is, in the current state of the project, very useful to use
"grep" on the
424 text output to filter by specific event fields. You can later copy the timestamp
425 of the events to the clipboard and paste them in the GUI by clicking on the
426 bottom right label
"Current time". Support for this type of filtering should
427 be added to the filter module soon.
431 Starting from LTTng
0.5.105 and ltt-control
0.20, a new mode can be used :
432 hybrid. It can be especially useful when studying big workloads on a long period
435 When using this mode, the most important, low rate control information will be
436 recorded during all the trace by lttd (i.e. process creation/exit). The high
437 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
438 flight recorder buffer (now named flight-channelname_X).
440 The following lttctl commands take an hybrid trace :
442 Create trace channel, start lttd on normal channels, start tracing:
444 lttctl -C -w /tmp/trace2 -o channel.kernel.overwrite=
1 trace2
447 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
449 lttctl -D -w /tmp/trace2 trace2
452 Each
"overwrite" channel is flight recorder channel.
454 <li>Flight recorder mode
</li>
456 The flight recorder mode writes data into overwritten buffers for all channels,
457 including control channels, except for the facilities tracefiles. It consists of
458 setting all channels to
"overwrite".
460 The following lttctl commands take a flight recorder trace :
462 lttctl -C -w /tmp/trace3 -o channel.all.overwrite=
1 trace3
464 lttctl -D -w /tmp/trace3 trace3
470 <h2><a href=
"#TOCsection3" name=
"section3">Adding new instrumentations with the
474 <h3><a href=
"#TOCkerneltp" name=
"kerneltp">Adding kernel
475 instrumentation
</a></h3>
479 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>
481 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
485 href=
"http://git.kernel.org/?p=linux/kernel/git/compudj/linux-2.6-lttng.git;a=tree;f=ltt/probes">ltt/probes/
</a>
486 for LTTng probe examples.
488 <h3><a href=
"#TOCusertp" name=
"usertp">Adding userspace instrumentation
</a></h3>
490 <li>Add new events to userspace programs with
491 <a href=
"http://ltt.polymtl.ca/packages/">userspace markers packages
</a></li>
494 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
495 allows inserting markers in executables and libraries, currently only on x86_32
498 href=
"http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2">markers-userspace-
0.5.tar.bz2
</a> or more recent.
501 Note that a new design document for a
3rd generation of tracepoint/marker-based
502 userspace tracing is available at
<a
503 href=
"http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/ust.html">LTTng User-space Tracing
504 Design
</a>. This new infrastructure is not yet implemented.
507 The easy quick-and-dirty way to perform userspace tracing is currently to write
508 an string to /mnt/debugfs/ltt/write_event. See
<a
509 href=
"#userspacetracing">Userspace tracing
</a> in the
510 installation for sources section of this document.
514 <h2><a href=
"#TOCsection4" name=
"section4">Creating Debian or RPM packages
</a></h2>
517 <h3><a href=
"#TOCpkgdebian" name=
"pkgdebian">Create custom LTTV Debian packages
</a></h3>
520 Use : dpkg-buildpackage -rfakeroot
523 You should then have your LTTV .deb files created for your architecture.
525 <h3><a href=
"#TOCpkglttng" name=
"pkglttng">Create custom LTTng packages
</a></h3>
527 For building LTTng Debian packages :
528 get the build tree with patches applies as explained in section
2.
531 make menuconfig (or xconfig or config) (customize your configuration)
532 make-kpkg kernel_image
535 You will then see your freshly created .deb in /usr/src. Install it with
537 dpkg -i /usr/src/(image-name).deb
540 Then, follow the section
"Editing the system wide configuration" in section
2.