1 Linux Trace Toolkit Quickstart
2 ------------------------------
3 Author : Mathieu Desnoyers, September 2005
4 Last update : July 31, 2008
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 0.12 tracer on a linux 2.6.X
18 kernel. You will also find instructions for installation of LTTV 0.8.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 [*] Activate tracepoints
170 [*] Activate userspace markers ABI
171 <*> Compile generic tracing probes
172 Linux Trace Toolkit --->
173 [LTTng fine-grained-timestamping]
174 [*] Linux Trace Toolkit Instrumentation Support
175 <M> or <*> Linux Trace Toolkit Relay+DebugFS Support
176 <M> or <*> Linux Trace Toolkit Serializer
177 <M> or <*> Linux Trace Toolkit Marker Control
178 <M> or <*> Linux Trace Toolkit Tracer
179 It makes no difference for the rest of the procedure whether the Tracer
180 is compiled built-in or as a module.
182 [*] Align Linux Trace Toolkit Traces
183 <M> Linux Trace Toolkit Netlink Controller
184 <M> Linux Trace Toolkit State Dump
185 your choice (see < Help >) :
186 [ ] Write heartbeat event to shrink traces
187 [ ] Support trace extraction from crash dump
193 (if necessary, create a initrd with mkinitrd or your preferate alternative)
194 (mkinitrd -o /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx)
199 Select the Linux 2.6.17-lttng-0.x.xx kernel in your boot loader.
202 cp vmlinux.strip /boot/vmlinux-2.6.X-lttng-0.x.xx
203 cp System.map /boot/System.map-2.6.X-lttng-0.x.xx
204 cp .config /boot/config-2.6.X-lttng-0.x.xx
205 depmod -ae -F /boot/System.map-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
206 mkinitrd /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
207 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
208 that comes first is the default kernel)
210 select the right entry at the yaboot prompt (see choices : tab, select : type
211 the kernel name followed by enter)
212 Select the Linux 2.6.17-lttng-0.x.xx kernel in your boot loader.
217 * Editing the system wide configuration
219 You must activate debugfs and specify a mount point. This is typically done in
220 fstab such that it happens at boot time.
222 If you have never used DebugFS before, these operation would do this for you :
225 cp /etc/fstab /etc/fstab.lttng.bkp
226 echo "debugfs /mnt/debugfs debugfs rw 0 0" >> /etc/fstab
228 then, rebooting or issuing the following command will activate debugfs :
232 You need to load the LTT modules to be able to control tracing from user
233 space. This is done by issuing the following commands. Note however
234 these commands load all LTT modules. Depending on what options you chose to
235 compile statically, you may not need to issue all these commands.
238 modprobe ltt-marker-control
240 modprobe ltt-serialize
243 modprobe kernel-trace
247 modprobe syscall-trace
248 #if locking tracing is wanted, uncomment the following
249 #modprobe lockdep-trace
251 If you want to have complete information about the kernel state (including all
252 the process names), you need to load the ltt-statedump module. This is done by
253 issuing the command :
255 modprobe ltt-statedump
257 You can automate at boot time loading the ltt-control module by :
259 cp /etc/modules /etc/modules.bkp
260 echo ltt-control >> /etc/modules
261 echo ltt-marker-control >> /etc/modules
262 echo ltt-tracer >> /etc/modules
263 echo ltt-serialize >> /etc/modules
264 echo ltt-relay >> /etc/modules
265 echo ipc-trace >> /etc/modules
266 echo kernel-trace >> /etc/modules
267 echo mm-trace >> /etc/modules
268 echo net-trace >> /etc/modules
269 echo fs-trace >> /etc/modules
270 #if locking tracing is wanted, uncomment the following
271 #echo lockdep-trace >> /etc/modules
274 * Getting and installing the ltt-control package (on the traced machine)
275 (note : the ltt-control package contains lttd and lttctl. Although it has the
276 same name as the ltt-control kernel module, they are *not* the same thing.)
279 wget http://ltt.polymtl.ca/lttng/ltt-control-0.x-xxxx2006.tar.gz
280 gzip -cd ltt-control-0.x-xxxx2006.tar.gz | tar xvof -
281 cd ltt-control-0.x-xxxx2006
282 (refer to README to see the development libraries that must be installed on you
288 * Getting and installing the markers-userspace package for user space tracing
289 See http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2 or more recent.
292 * Getting and installing the LTTV package (on the visualisation machine, same or
293 different from the visualisation machine)
297 wget http://ltt.polymtl.ca/packages/lttv-0.x.xx-xxxx2008.tar.gz
298 gzip -cd lttv-0.x.xx-xxxx2008.tar.gz | tar xvof -
299 cd lttv-0.x.xx-xxxx2008
300 (refer to README to see the development libraries that must be installed on your
309 ***********************************************************
310 ** Section 3 * Using LTTng and LTTV **
311 ***********************************************************
313 * IMPORTANT : Arm Linux Kernel Markers after each boot
317 * Use graphical LTTV to control tracing and analyse traces
319 lttv-gui (or /usr/local/bin/lttv-gui)
320 - Spot the "Tracing Control" icon : click on it
321 (it's a traffic light icon)
322 - enter the root password
326 * You should now see a trace
328 * Use text mode LTTng to control tracing
330 The tracing can be controlled from a terminal by using the lttctl command (as
335 lttctl -n trace -d -l /mnt/debugfs/ltt -t /tmp/trace
337 Stop tracing and destroy trace channels :
341 see lttctl --help for details.
343 (note : to see if the buffers has been filled, look at the dmesg output after
344 lttctl -R or after stopping tracing from the GUI, it will show an event lost
345 count. If it is the case, try using larger buffers. See lttctl --help to learn
350 Feel free to look in /usr/local/lib/lttv/plugins to see all the text and
351 graphical plugins available.
353 For example, a simple trace dump in text format is available with :
355 lttv -m textDump -t /tmp/trace
357 see lttv -m textDump --help for detailed command line options of textDump.
359 It is, in the current state of the project, very useful to use "grep" on the
360 text output to filter by specific event fields. You can later copy the timestamp
361 of the events to the clipboard and paste them in the GUI by clicking on the
362 bottom right label "Current time". Support for this type of filtering should
363 be added to the filter module soon.
367 Starting from LTTng 0.5.105 and ltt-control 0.20, a new mode can be used :
368 hybrid. It can be especially useful when studying big workloads on a long period
371 When using this mode, the most important, low rate control information will be
372 recorded during all the trace by lttd (i.e. process creation/exit). The high
373 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
374 flight recorder buffer (now named flight-channelname_X).
376 The following lttctl commands take an hybrid trace :
378 Create trace channel, start lttd on normal channels, start tracing:
379 lttctl -n tracename -d -l /mnt/debugfs/ltt -t /tmp/trace1 -m hybrid
381 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
382 lttctl -n tracename -f -l /mnt/debugfs/ltt -t /tmp/trace1 -m hybrid
385 We will need to tweak what we consider "important" medium rate events. For
386 instance, thread branding events are actually considered a "high rate" event
387 when it should be considered "medium rate". The same should apply for the
388 state dump process enumeration.
390 * Flight recorder mode
392 The flight recorder mode writes data into overwritten buffers for all channels,
393 including control channels, except for the facilities tracefiles.
395 The following lttctl commands take a flight recorder trace :
397 lttctl -n trace -c -m flight
398 lttd -n -d -t /tmp/trace -c /mnt/debugfs/ltt/trace
402 lttd -f -d -t /tmp/trace -c /mnt/debugfs/ltt/trace
406 **************************************************************
407 ** Section 4 * Adding new instrumentations with the markers **
408 **************************************************************
410 See Documentation/markers.txt and Documentation/tracepoints.txt in your kernel
413 * Add new events to userspace programs with userspace markers
414 http://ltt.polymtl.ca/packages/
416 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
417 allows inserting markers in executables and libraries, currently only on x86_32