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)
125 * Getting the LTTng packages
130 (see http://ltt.polymtl.ca/lttng for package listing)
131 wget http://ltt.polymtl.ca/lttng/patch-2.6.X-lttng-0.x.xx.tar.bz2
132 bzip2 -cd patch-2.6.X-lttng-0.x.xx.tar.bz2 | tar xvof -
135 * Getting LTTng kernel sources
139 wget http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.X.tar.bz2
140 bzip2 -cd linux-2.6.X.tar.bz2 | tar xvof -
142 - For LTTng 0.9.4- cat /usr/src/lttng/patch*-2.6.X-lttng-0.x.xx* | patch -p1
143 - For LTTng 0.9.5+ apply the patches in the order specified in the series file,
146 mv linux-2.6.X linux-2.6.X-lttng-0.x.xx
149 * Installing a LTTng kernel
152 cd /usr/src/linux-2.6.X-lttng-0.x.xx
153 make menuconfig (or make xconfig or make config)
154 Select the < Help > button if you are not familiar with kernel
156 Items preceded by [*] means they has to be built into the kernel.
157 Items preceded by [M] means they has to be built as modules.
158 Items preceded by [ ] means they should be removed.
159 go to the "General setup" section
160 Select the following options :
161 [*] Activate tracepoints
163 [*] Activate userspace markers ABI
164 <*> Compile generic tracing probes
165 Linux Trace Toolkit --->
166 [LTTng fine-grained-timestamping]
167 [*] Linux Trace Toolkit Instrumentation Support
168 <M> or <*> Linux Trace Toolkit Relay+DebugFS Support
169 <M> or <*> Linux Trace Toolkit Serializer
170 <M> or <*> Linux Trace Toolkit Marker Control
171 <M> or <*> Linux Trace Toolkit Tracer
172 It makes no difference for the rest of the procedure whether the Tracer
173 is compiled built-in or as a module.
175 [*] Align Linux Trace Toolkit Traces
176 <M> Linux Trace Toolkit Netlink Controller
177 <M> Linux Trace Toolkit State Dump
178 your choice (see < Help >) :
179 [ ] Write heartbeat event to shrink traces
180 [ ] Support trace extraction from crash dump
186 (if necessary, create a initrd with mkinitrd or your preferate alternative)
187 (mkinitrd -o /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx)
192 Select the Linux 2.6.17-lttng-0.x.xx kernel in your boot loader.
195 cp vmlinux.strip /boot/vmlinux-2.6.X-lttng-0.x.xx
196 cp System.map /boot/System.map-2.6.X-lttng-0.x.xx
197 cp .config /boot/config-2.6.X-lttng-0.x.xx
198 depmod -ae -F /boot/System.map-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
199 mkinitrd /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
200 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
201 that comes first is the default kernel)
203 select the right entry at the yaboot prompt (see choices : tab, select : type
204 the kernel name followed by enter)
205 Select the Linux 2.6.17-lttng-0.x.xx kernel in your boot loader.
210 * Editing the system wide configuration
212 You must activate debugfs and specify a mount point. This is typically done in
213 fstab such that it happens at boot time.
215 If you have never used DebugFS before, these operation would do this for you :
218 cp /etc/fstab /etc/fstab.lttng.bkp
219 echo "debugfs /mnt/debugfs debugfs rw 0 0" >> /etc/fstab
221 then, rebooting or issuing the following command will activate debugfs :
225 You need to load the LTT modules to be able to control tracing from user
226 space. This is done by issuing the following commands. Note however
227 these commands load all LTT modules. Depending on what options you chose to
228 compile statically, you may not need to issue all these commands.
231 modprobe ltt-marker-control
233 modprobe ltt-serialize
236 modprobe kernel-trace
240 modprobe syscall-trace
241 #if locking tracing is wanted, uncomment the following
242 #modprobe lockdep-trace
244 If you want to have complete information about the kernel state (including all
245 the process names), you need to load the ltt-statedump module. This is done by
246 issuing the command :
248 modprobe ltt-statedump
250 You can automate at boot time loading the ltt-control module by :
252 cp /etc/modules /etc/modules.bkp
253 echo ltt-control >> /etc/modules
254 echo ltt-marker-control >> /etc/modules
255 echo ltt-tracer >> /etc/modules
256 echo ltt-serialize >> /etc/modules
257 echo ltt-relay >> /etc/modules
258 echo ipc-trace >> /etc/modules
259 echo kernel-trace >> /etc/modules
260 echo mm-trace >> /etc/modules
261 echo net-trace >> /etc/modules
262 echo fs-trace >> /etc/modules
263 #if locking tracing is wanted, uncomment the following
264 #echo lockdep-trace >> /etc/modules
267 * Getting and installing the ltt-control package (on the traced machine)
268 (note : the ltt-control package contains lttd and lttctl. Although it has the
269 same name as the ltt-control kernel module, they are *not* the same thing.)
272 wget http://ltt.polymtl.ca/lttng/ltt-control-0.x-xxxx2006.tar.gz
273 gzip -cd ltt-control-0.x-xxxx2006.tar.gz | tar xvof -
274 cd ltt-control-0.x-xxxx2006
275 (refer to README to see the development libraries that must be installed on you
281 * Getting and installing the markers-userspace package for user space tracing
282 See http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2 or more recent.
285 * Getting and installing the LTTV package (on the visualisation machine, same or
286 different from the visualisation machine)
290 wget http://ltt.polymtl.ca/packages/lttv-0.x.xx-xxxx2008.tar.gz
291 gzip -cd lttv-0.x.xx-xxxx2008.tar.gz | tar xvof -
292 cd lttv-0.x.xx-xxxx2008
293 (refer to README to see the development libraries that must be installed on your
302 ***********************************************************
303 ** Section 3 * Using LTTng and LTTV **
304 ***********************************************************
306 * IMPORTANT : Arm Linux Kernel Markers after each boot
310 * Use graphical LTTV to control tracing and analyse traces
312 lttv-gui (or /usr/local/bin/lttv-gui)
313 - Spot the "Tracing Control" icon : click on it
314 (it's a traffic light icon)
315 - enter the root password
319 * You should now see a trace
321 * Use text mode LTTng to control tracing
323 The tracing can be controlled from a terminal by using the lttctl command (as
328 lttctl -n trace -d -l /mnt/debugfs/ltt -t /tmp/trace
330 Stop tracing and destroy trace channels :
334 see lttctl --help for details.
336 (note : to see if the buffers has been filled, look at the dmesg output after
337 lttctl -R or after stopping tracing from the GUI, it will show an event lost
338 count. If it is the case, try using larger buffers. See lttctl --help to learn
343 Feel free to look in /usr/local/lib/lttv/plugins to see all the text and
344 graphical plugins available.
346 For example, a simple trace dump in text format is available with :
348 lttv -m textDump -t /tmp/trace
350 see lttv -m textDump --help for detailed command line options of textDump.
352 It is, in the current state of the project, very useful to use "grep" on the
353 text output to filter by specific event fields. You can later copy the timestamp
354 of the events to the clipboard and paste them in the GUI by clicking on the
355 bottom right label "Current time". Support for this type of filtering should
356 be added to the filter module soon.
360 Starting from LTTng 0.5.105 and ltt-control 0.20, a new mode can be used :
361 hybrid. It can be especially useful when studying big workloads on a long period
364 When using this mode, the most important, low rate control information will be
365 recorded during all the trace by lttd (i.e. process creation/exit). The high
366 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
367 flight recorder buffer (now named flight-channelname_X).
369 The following lttctl commands take an hybrid trace :
371 Create trace channel, start lttd on normal channels, start tracing:
372 lttctl -n tracename -d -l /mnt/debugfs/ltt -t /tmp/trace1 -m hybrid
374 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
375 lttctl -n tracename -f -l /mnt/debugfs/ltt -t /tmp/trace1 -m hybrid
378 We will need to tweak what we consider "important" medium rate events. For
379 instance, thread branding events are actually considered a "high rate" event
380 when it should be considered "medium rate". The same should apply for the
381 state dump process enumeration.
383 * Flight recorder mode
385 The flight recorder mode writes data into overwritten buffers for all channels,
386 including control channels, except for the facilities tracefiles.
388 The following lttctl commands take a flight recorder trace :
390 lttctl -n trace -c -m flight
391 lttd -n -d -t /tmp/trace -c /mnt/debugfs/ltt/trace
395 lttd -f -d -t /tmp/trace -c /mnt/debugfs/ltt/trace
399 **************************************************************
400 ** Section 4 * Adding new instrumentations with the markers **
401 **************************************************************
403 See Documentation/markers.txt and Documentation/tracepoints.txt in your kernel
406 * Add new events to userspace programs with userspace markers
407 http://ltt.polymtl.ca/packages/
409 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
410 allows inserting markers in executables and libraries, currently only on x86_32