1 <!DOCTYPE html PUBLIC
"-//W3C//DTD HTML 4.01 Transitional//EN">
4 <title>Linux Trace Toolkit Quickstart
</title>
8 <h1>Linux Trace Toolkit Quickstart
</h1>
11 Author : Mathieu Desnoyers, September
2005<br>
12 Last update : January
21st,
2009<br>
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=
"#section2" name=
"TOCsection2">Using LTTng and LTTV
</a></li>
21 <li><a href=
"#section3" name=
"TOCsection3">Adding kernel and user-space
28 <h2><a href=
"#TOCintro" name=
"intro">Introduction
</a></h2>
30 This document is made of three parts : the first one explains how
31 to install LTTng and LTTV from sources, the second one describes the steps
32 to follow to trace a system and view it. The third and last part explains
33 briefly how to add a new trace point to the kernel and to user space
37 These operations are made for installing the LTTng
0.86 tracer on a linux
2.6.X
38 kernel. You will also find instructions for installation of LTTV
0.12.x : the
39 Linux Trace Toolkit Viewer.
42 To see the list of compatibilities between LTTng, ltt-control, LTTV, please
45 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 ** Current development status **
<br>
56 Supported architectures :
58 <li> PowerPC
32 and
64 bits
59 <li> ARM (with limited timestamping precision, e.g.
1HZ. Need
60 architecture-specific support for better precision)
65 supported architectures :
<br>
67 <li> PowerPC
32 and
64 bits
68 <li> Possibly others. Takes care of endianness and type size difference between
69 the LTTng traces and the LTTV analysis tool.
73 ***********************************************************
74 ** Section
1 * Installation from Debian or RPM packages **
75 ***********************************************************
77 * Create custom LTTV Debian packages
79 Use : dpkg-buildpackage -rfakeroot
81 You should then have your LTTV .deb files created for your architecture.
83 * Create custom LTTng packages
85 For building LTTng Debian packages :
87 Get the build tree with patches applies as explained in section
2.
89 make menuconfig (or xconfig or config) (customize your configuration)
90 make-kpkg kernel_image
92 You will then see your freshly created .deb in /usr/src. Install it with
93 dpkg -i /usr/src/(image-name).deb
95 Then, follow the section
"Editing the system wide configuration" in section
2.
98 ***********************************************************
99 ** Section
2 * Installation from sources **
100 ***********************************************************
104 Tools needed to follow the package download steps :
111 You have to install the standard development libraries and programs necessary
112 to compile a kernel :
114 (from Documentation/Changes in the Linux kernel tree)
115 o Gnu C
2.95.3 # gcc --version
116 o Gnu make
3.79.1 # make --version
117 o binutils
2.12 # ld -v
118 o util-linux
2.10o # fdformat --version
119 o module-init-tools
0.9.10 # depmod -V
121 You might also want to have libncurses5 to have the text mode kernel
122 configuration menu, but there are alternatives.
124 Prerequisites for LTTV
0.x.x installation are :
127 gtk
2.4 or better development libraries
128 (Debian : libgtk2.0, libgtk2.0-dev)
129 (Fedora : gtk2, gtk2-devel)
130 note : For Fedora users : this might require at least core
3 from Fedora,
131 or you might have to compile your own GTK2 library.
132 glib
2.4 or better development libraries
133 (Debian : libglib2.0-
0, libglib2.0-dev)
134 (Fedora : glib2, glib2-devel)
135 libpopt development libraries
136 (Debian : libpopt0, libpopt-dev)
138 libpango development libraries
139 (Debian : libpango1.0, libpango1.0-dev)
140 (Fedora : pango, pango-devel)
141 libc6 development librairies
142 (Debian : libc6, libc6-dev)
143 (Fedora : glibc, glibc)
147 See the list of compatibilities between LTTng, ltt-control, LTTV and
148 markers-userspace at :
149 http://ltt.polymtl.ca
> LTTng+LTTV versions compatibility
153 * Getting the LTTng packages
158 (see http://ltt.polymtl.ca/lttng for package listing)
159 wget http://ltt.polymtl.ca/lttng/patch-
2.6.X-lttng-
0.x.xx.tar.bz2
160 bzip2 -cd patch-
2.6.X-lttng-
0.x.xx.tar.bz2 | tar xvof -
163 * Getting LTTng kernel sources
167 wget http://kernel.org/pub/linux/kernel/v2.6/linux-
2.6.X.tar.bz2
168 bzip2 -cd linux-
2.6.X.tar.bz2 | tar xvof -
170 - For LTTng
0.9.4- cat /usr/src/lttng/patch*-
2.6.X-lttng-
0.x.xx* | patch -p1
171 - For LTTng
0.9.5+ apply the patches in the order specified in the series file,
174 mv linux-
2.6.X linux-
2.6.X-lttng-
0.x.xx
177 * Installing a LTTng kernel
180 cd /usr/src/linux-
2.6.X-lttng-
0.x.xx
181 make menuconfig (or make xconfig or make config)
182 Select the < Help
> button if you are not familiar with kernel
184 Items preceded by [*] means they has to be built into the kernel.
185 Items preceded by [M] means they has to be built as modules.
186 Items preceded by [ ] means they should be removed.
187 go to the
"General setup" section
188 Select the following options :
189 [*] Prompt for development and/or incomplete code/drivers
191 [*] Activate userspace markers ABI (experimental, optional)
192 [*] Immediate value optimization (optional)
193 [*] Linux Trace Toolkit Next Generation (LTTng) --->
194 <M> or <*
> Compile lttng tracing probes
195 <M> or <*
> Linux Trace Toolkit High-speed Lockless Data Relay
196 <M> or <*
> Linux Trace Toolkit Lock-Protected Data Relay
197 <M> or <*
> Linux Trace Toolkit Serializer
198 <M> or <*
> Linux Trace Toolkit Marker Control
199 <M> or <*
> Linux Trace Toolkit Tracer
200 [*] Align Linux Trace Toolkit Traces
201 <M> or <*
> Support logging events from userspace
202 [*] Support trace extraction from crash dump
203 <M> or <*
> Linux Trace Toolkit Trace Controller
204 <M> or <*
> Linux Trace Toolkit State Dump
210 (if necessary, create a initrd with mkinitrd or your preferate alternative)
211 (mkinitrd -o /boot/initrd.img-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx)
216 Select the Linux
2.6.X-lttng-
0.x.xx kernel in your boot loader.
219 cp vmlinux.strip /boot/vmlinux-
2.6.X-lttng-
0.x.xx
220 cp System.map /boot/System.map-
2.6.X-lttng-
0.x.xx
221 cp .config /boot/config-
2.6.X-lttng-
0.x.xx
222 depmod -ae -F /boot/System.map-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx
223 mkinitrd /boot/initrd.img-
2.6.X-lttng-
0.x.xx
2.6.X-lttng-
0.x.xx
224 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
225 that comes first is the default kernel)
227 select the right entry at the yaboot prompt (see choices : tab, select : type
228 the kernel name followed by enter)
229 Select the Linux
2.6.X-lttng-
0.x.xx kernel in your boot loader.
234 * Editing the system wide configuration
236 You must activate debugfs and specify a mount point. This is typically done in
237 fstab such that it happens at boot time.
239 If you have never used DebugFS before, these operation would do this for you :
242 cp /etc/fstab /etc/fstab.lttng.bkp
243 echo
"debugfs /mnt/debugfs debugfs rw 0 0" >> /etc/fstab
245 then, rebooting or issuing the following command will activate debugfs :
249 You need to load the LTT modules to be able to control tracing from user
250 space. This is done by issuing the following commands. Note however
251 these commands load all LTT modules. Depending on what options you chose to
252 compile statically, you may not need to issue all these commands.
254 modprobe ltt-trace-control
255 modprobe ltt-marker-control
257 modprobe ltt-serialize
260 modprobe kernel-trace
266 modprobe syscall-trace
268 #if locking tracing is wanted, uncomment the following
269 #modprobe lockdep-trace
271 If you want to have complete information about the kernel state (including all
272 the process names), you need to load the ltt-statedump module. This is done by
273 issuing the command :
275 modprobe ltt-statedump
277 You can automate at boot time loading the ltt-control module by :
279 cp /etc/modules /etc/modules.bkp
280 echo ltt-trace-control
>> /etc/modules
281 echo ltt-marker-control
>> /etc/modules
282 echo ltt-tracer
>> /etc/modules
283 echo ltt-serialize
>> /etc/modules
284 echo ltt-relay
>> /etc/modules
285 echo ipc-trace
>> /etc/modules
286 echo kernel-trace
>> /etc/modules
287 echo mm-trace
>> /etc/modules
288 echo net-trace
>> /etc/modules
289 echo fs-trace
>> /etc/modules
290 echo jbd2-trace
>> /etc/modules
291 echo ext4-trace
>> /etc/modules
292 echo syscall-trace
>> /etc/modules
293 echo trap-trace
>> /etc/modules
294 #if locking tracing is wanted, uncomment the following
295 #echo lockdep-trace
>> /etc/modules
298 * Getting and installing the ltt-control package (on the traced machine)
299 (note : the ltt-control package contains lttd and lttctl. Although it has the
300 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
315 Make sure you selected the kernel menuconfig option :
316 <M> or <*
> Support logging events from userspace
317 And that the ltt-userspace-event kernel module is loaded if selected as a
320 Simple userspace tracing is available through
321 echo
"some text to record" > /mnt/debugfs/ltt/write_event
323 It will appear in the trace under event :
328 * Getting and installing the LTTV package (on the visualisation machine, same or
329 different from the visualisation machine)
333 wget http://ltt.polymtl.ca/packages/lttv-
0.x.xx-xxxx2008.tar.gz
334 gzip -cd lttv-
0.x.xx-xxxx2008.tar.gz | tar xvof -
335 cd lttv-
0.x.xx-xxxx2008
336 (refer to README to see the development libraries that must be installed on your
343 * Getting and installing the markers-userspace package for user space tracing
345 See http://ltt.polymtl.ca/packages/markers-userspace-
0.5.tar.bz2 or more recent.
349 ***********************************************************
350 ** Section
3 * Using LTTng and LTTV **
351 ***********************************************************
353 * IMPORTANT : Arm Linux Kernel Markers after each boot
357 * Use graphical LTTV to control tracing and analyse traces
359 lttv-gui (or /usr/local/bin/lttv-gui)
360 - Spot the
"Tracing Control" icon : click on it
361 (it's a traffic light icon)
362 - enter the root password
366 * You should now see a trace
368 * Use text mode LTTng to control tracing
370 The tracing can be controlled from a terminal by using the lttctl command (as
375 lttctl -C -w /tmp/trace1 trace1
377 Stop tracing and destroy trace channels :
381 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.)
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
398 see lttv -m textDump --help for detailed command line options of textDump.
400 It is, in the current state of the project, very useful to use
"grep" on the
401 text output to filter by specific event fields. You can later copy the timestamp
402 of the events to the clipboard and paste them in the GUI by clicking on the
403 bottom right label
"Current time". Support for this type of filtering should
404 be added to the filter module soon.
408 Starting from LTTng
0.5.105 and ltt-control
0.20, a new mode can be used :
409 hybrid. It can be especially useful when studying big workloads on a long period
412 When using this mode, the most important, low rate control information will be
413 recorded during all the trace by lttd (i.e. process creation/exit). The high
414 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
415 flight recorder buffer (now named flight-channelname_X).
417 The following lttctl commands take an hybrid trace :
419 Create trace channel, start lttd on normal channels, start tracing:
420 lttctl -C -w /tmp/trace2 -o channel.kernel.overwrite=
1 trace2
422 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
423 lttctl -D -w /tmp/trace2 trace2
425 Each
"overwrite" channel is flight recorder channel.
427 * Flight recorder mode
429 The flight recorder mode writes data into overwritten buffers for all channels,
430 including control channels, except for the facilities tracefiles. It consists of
431 setting all channels to
"overwrite".
433 The following lttctl commands take a flight recorder trace :
435 lttctl -C -w /tmp/trace3 -o channel.all.overwrite=
1 trace3
437 lttctl -D -w /tmp/trace3 trace3
440 **************************************************************
441 ** Section
4 * Adding new instrumentations with the markers **
442 **************************************************************
444 See Documentation/markers.txt and Documentation/tracepoints.txt in your kernel
447 * Add new events to userspace programs with userspace markers
448 http://ltt.polymtl.ca/packages/
450 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
451 allows inserting markers in executables and libraries, currently only on x86_32