1 Linux Trace Toolkit Quickstart
2 ------------------------------
3 Author : Mathieu Desnoyers, September 2005
4 Last update : January 9th, 2009
7 This document is made of four parts : the first one explains how to install
8 LTTng and LTTV from Debian and RPM binary packages, the second one explains how
9 to install LTTng and LTTV from sources and the third one describes the steps
10 to follow to trace a system and view it. The fourth and last part explains
11 briefly how to add a new trace point to the kernel and to user space
14 What you will typically want is to read sections 2 and 3 : install LTTng from
17 These operations are made for installing the LTTng 0.74 tracer on a linux 2.6.X
18 kernel. You will also find instructions for installation of LTTV 0.12.x : the
19 Linux Trace Toolkit Viewer.
21 To see the list of compatibilities between LTTng, ltt-control, LTTV and
22 markers-userspace, please refer to :
23 http://ltt.polymtl.ca > LTTng+LTTV versions compatibility
27 The following lttng patch is necessary to have the tracing hooks in the kernel.
28 The following ltt-control module controls the tracing.
30 Required programs and libraries are assumed to be automatically installed in an
31 installation with Debian or RPM packages. In the case of an installation from
32 sources, the dependencies are listed.
35 ** Current development status **
38 supported architectures :
39 Intel Pentium (UP/SMP) with TSC
40 PowerPC 32 and 64 bits
43 C2 Microsystems (variant of MIPS)
46 supported architectures :
49 PowerPC 32 and 64 bits
52 ***********************************************************
53 ** Section 1 * Installation from Debian or RPM packages **
54 ***********************************************************
56 * Create custom LTTV Debian packages
58 Use : dpkg-buildpackage -rfakeroot
60 You should then have your LTTV .deb files created for your architecture.
62 * Create custom LTTng packages
64 For building LTTng Debian packages :
66 Get the build tree with patches applies as explained in section 2.
68 make menuconfig (or xconfig or config) (customize your configuration)
69 make-kpkg kernel_image
71 You will then see your freshly created .deb in /usr/src. Install it with
72 dpkg -i /usr/src/(image-name).deb
74 Then, follow the section "Editing the system wide configuration" in section 2.
77 ***********************************************************
78 ** Section 2 * Installation from sources **
79 ***********************************************************
83 Tools needed to follow the package download steps :
90 You have to install the standard development libraries and programs necessary
93 (from Documentation/Changes in the Linux kernel tree)
94 o Gnu C 2.95.3 # gcc --version
95 o Gnu make 3.79.1 # make --version
96 o binutils 2.12 # ld -v
97 o util-linux 2.10o # fdformat --version
98 o module-init-tools 0.9.10 # depmod -V
100 You might also want to have libncurses5 to have the text mode kernel
101 configuration menu, but there are alternatives.
103 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)
126 See the list of compatibilities between LTTng, ltt-control, LTTV and
127 markers-userspace at :
128 http://ltt.polymtl.ca > LTTng+LTTV versions compatibility
132 * Getting the LTTng packages
137 (see http://ltt.polymtl.ca/lttng for package listing)
138 wget http://ltt.polymtl.ca/lttng/patch-2.6.X-lttng-0.x.xx.tar.bz2
139 bzip2 -cd patch-2.6.X-lttng-0.x.xx.tar.bz2 | tar xvof -
142 * Getting LTTng kernel sources
146 wget http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.X.tar.bz2
147 bzip2 -cd linux-2.6.X.tar.bz2 | tar xvof -
149 - For LTTng 0.9.4- cat /usr/src/lttng/patch*-2.6.X-lttng-0.x.xx* | patch -p1
150 - For LTTng 0.9.5+ apply the patches in the order specified in the series file,
153 mv linux-2.6.X linux-2.6.X-lttng-0.x.xx
156 * Installing a LTTng kernel
159 cd /usr/src/linux-2.6.X-lttng-0.x.xx
160 make menuconfig (or make xconfig or make config)
161 Select the < Help > button if you are not familiar with kernel
163 Items preceded by [*] means they has to be built into the kernel.
164 Items preceded by [M] means they has to be built as modules.
165 Items preceded by [ ] means they should be removed.
166 go to the "General setup" section
167 Select the following options :
168 [*] Prompt for development and/or incomplete code/drivers
170 [*] Activate userspace markers ABI (experimental, optional)
171 [*] Immediate value optimization (optional)
172 [*] Linux Trace Toolkit Next Generation (LTTng) --->
173 <M> or <*> Compile lttng tracing probes
174 <M> or <*> Linux Trace Toolkit High-speed Lockless Data Relay
175 <M> or <*> Linux Trace Toolkit Lock-Protected Data Relay
176 <M> or <*> Linux Trace Toolkit Serializer
177 <M> or <*> Linux Trace Toolkit Marker Control
178 <M> or <*> Linux Trace Toolkit Tracer
179 [*] Align Linux Trace Toolkit Traces
180 <M> or <*> Support logging events from userspace
181 [*] Support trace extraction from crash dump
182 <M> or <*> Linux Trace Toolkit Trace Controller
183 <M> or <*> Linux Trace Toolkit State Dump
189 (if necessary, create a initrd with mkinitrd or your preferate alternative)
190 (mkinitrd -o /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx)
195 Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
198 cp vmlinux.strip /boot/vmlinux-2.6.X-lttng-0.x.xx
199 cp System.map /boot/System.map-2.6.X-lttng-0.x.xx
200 cp .config /boot/config-2.6.X-lttng-0.x.xx
201 depmod -ae -F /boot/System.map-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
202 mkinitrd /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
203 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
204 that comes first is the default kernel)
206 select the right entry at the yaboot prompt (see choices : tab, select : type
207 the kernel name followed by enter)
208 Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
213 * Editing the system wide configuration
215 You must activate debugfs and specify a mount point. This is typically done in
216 fstab such that it happens at boot time.
218 If you have never used DebugFS before, these operation would do this for you :
221 cp /etc/fstab /etc/fstab.lttng.bkp
222 echo "debugfs /mnt/debugfs debugfs rw 0 0" >> /etc/fstab
224 then, rebooting or issuing the following command will activate debugfs :
228 You need to load the LTT modules to be able to control tracing from user
229 space. This is done by issuing the following commands. Note however
230 these commands load all LTT modules. Depending on what options you chose to
231 compile statically, you may not need to issue all these commands.
233 modprobe ltt-trace-control
234 modprobe ltt-marker-control
236 modprobe ltt-serialize
239 modprobe kernel-trace
245 modprobe syscall-trace
247 #if locking tracing is wanted, uncomment the following
248 #modprobe lockdep-trace
250 If you want to have complete information about the kernel state (including all
251 the process names), you need to load the ltt-statedump module. This is done by
252 issuing the command :
254 modprobe ltt-statedump
256 You can automate at boot time loading the ltt-control module by :
258 cp /etc/modules /etc/modules.bkp
259 echo ltt-trace-control >> /etc/modules
260 echo ltt-marker-control >> /etc/modules
261 echo ltt-tracer >> /etc/modules
262 echo ltt-serialize >> /etc/modules
263 echo ltt-relay >> /etc/modules
264 echo ipc-trace >> /etc/modules
265 echo kernel-trace >> /etc/modules
266 echo mm-trace >> /etc/modules
267 echo net-trace >> /etc/modules
268 echo fs-trace >> /etc/modules
269 echo jbd2-trace >> /etc/modules
270 echo ext4-trace >> /etc/modules
271 echo syscall-trace >> /etc/modules
272 echo trap-trace >> /etc/modules
273 #if locking tracing is wanted, uncomment the following
274 #echo lockdep-trace >> /etc/modules
277 * Getting and installing the ltt-control package (on the traced machine)
278 (note : the ltt-control package contains lttd and lttctl. Although it has the
279 same name as the ltt-control kernel module, they are *not* the same thing.)
282 wget http://ltt.polymtl.ca/lttng/ltt-control-0.x-xxxx2006.tar.gz
283 gzip -cd ltt-control-0.x-xxxx2008.tar.gz | tar xvof -
284 cd ltt-control-0.x-xxxx2006
285 (refer to README to see the development libraries that must be installed on you
294 Make sure you selected the kernel menuconfig option :
295 <M> or <*> Support logging events from userspace
296 And that the ltt-userspace-event kernel module is loaded if selected as a
299 Simple userspace tracing is available through
300 echo "some text to record" > /mnt/debugfs/ltt/write_event
302 It will appear in the trace under event :
307 * Getting and installing the LTTV package (on the visualisation machine, same or
308 different from the visualisation machine)
312 wget http://ltt.polymtl.ca/packages/lttv-0.x.xx-xxxx2008.tar.gz
313 gzip -cd lttv-0.x.xx-xxxx2008.tar.gz | tar xvof -
314 cd lttv-0.x.xx-xxxx2008
315 (refer to README to see the development libraries that must be installed on your
322 * Getting and installing the markers-userspace package for user space tracing
324 See http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2 or more recent.
328 ***********************************************************
329 ** Section 3 * Using LTTng and LTTV **
330 ***********************************************************
332 * IMPORTANT : Arm Linux Kernel Markers after each boot
336 * Use graphical LTTV to control tracing and analyse traces
338 lttv-gui (or /usr/local/bin/lttv-gui)
339 - Spot the "Tracing Control" icon : click on it
340 (it's a traffic light icon)
341 - enter the root password
345 * You should now see a trace
347 * Use text mode LTTng to control tracing
349 The tracing can be controlled from a terminal by using the lttctl command (as
354 lttctl -C -w /tmp/trace1 trace1
356 Stop tracing and destroy trace channels :
360 see lttctl --help for details.
362 (note : to see if the buffers has been filled, look at the dmesg output after
363 lttctl -R or after stopping tracing from the GUI, it will show an event lost
364 count. If it is the case, try using larger buffers. See lttctl --help to learn
365 how. lttv now also shows event lost messages in the console when loading a trace
366 with missing events or lost subbuffers.)
370 Feel free to look in /usr/local/lib/lttv/plugins to see all the text and
371 graphical plugins available.
373 For example, a simple trace dump in text format is available with :
375 lttv -m textDump -t /tmp/trace
377 see lttv -m textDump --help for detailed command line options of textDump.
379 It is, in the current state of the project, very useful to use "grep" on the
380 text output to filter by specific event fields. You can later copy the timestamp
381 of the events to the clipboard and paste them in the GUI by clicking on the
382 bottom right label "Current time". Support for this type of filtering should
383 be added to the filter module soon.
387 Starting from LTTng 0.5.105 and ltt-control 0.20, a new mode can be used :
388 hybrid. It can be especially useful when studying big workloads on a long period
391 When using this mode, the most important, low rate control information will be
392 recorded during all the trace by lttd (i.e. process creation/exit). The high
393 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
394 flight recorder buffer (now named flight-channelname_X).
396 The following lttctl commands take an hybrid trace :
398 Create trace channel, start lttd on normal channels, start tracing:
399 lttctl -C -w /tmp/trace2 -o channel.kernel.overwrite=1 trace2
401 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
402 lttctl -D -w /tmp/trace2 trace2
404 Each "overwrite" channel is flight recorder channel.
406 * Flight recorder mode
408 The flight recorder mode writes data into overwritten buffers for all channels,
409 including control channels, except for the facilities tracefiles. It consists of
410 setting all channels to "overwrite".
412 The following lttctl commands take a flight recorder trace :
414 lttctl -C -w /tmp/trace3 -o channel.all.overwrite=1 trace3
416 lttctl -D -w /tmp/trace3 trace3
419 **************************************************************
420 ** Section 4 * Adding new instrumentations with the markers **
421 **************************************************************
423 See Documentation/markers.txt and Documentation/tracepoints.txt in your kernel
426 * Add new events to userspace programs with userspace markers
427 http://ltt.polymtl.ca/packages/
429 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
430 allows inserting markers in executables and libraries, currently only on x86_32