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   8 <h1>Linux Trace Toolkit Next Generation User Documentation</h1>
   9
  10 Author : Mathieu Desnoyers, September 2005<br>
  11 Last update : January 21st, 2009<br>
  12 (originally known as the LTTng QUICKSTART guide)
  13
  14 <h2>Table of Contents</h2>
  15
  16 <ul>
  17 <li><a href="#intro" name="TOCintro">Introduction</a></li>
  18 <ul>
  19 <li><a href="#arch" name="TOCarch">Supported architectures</a></li>
  20 </ul>
  21
  22 <li><a href="#section1" name="TOCsection1">Installing LTTng and LTTV from
  23 sources</a></li>
  24 <ul>
  25 <li><a href="#prerequisites" name="TOCprerequisites">Prerequisistes</li>
  26 <li><a href="#getlttng" name="TOCgetlttng">Getting the LTTng packages</li>
  27 <li><a href="#getlttngsrc" name="TOCgetlttngsrc">Getting the LTTng kernel sources</li>
  28 <li><a href="#installlttng" name="TOCinstalllttng">Installing a LTTng kernel</li>
  29 <li><a href="#editconfig" name="TOCeditconfig">Editing the system wide
  30 configuration</a>
  31 <li><a href="#getlttctl" name="TOCgetlttctl">Getting and installing the
  32 ltt-control package</li>
  33 <li><a href="#userspacetracing" name="TOCuserspacetracing">Userspace Tracing</li>
  34 <li><a href="#getlttv" name="TOCgetlttv">Getting and installing the LTTV package</ul>
  35
  36 <li><a href="#section2" name="TOCsection2">Using LTTng and LTTV</a></li>
  37 <ul>
  38 <li><a href="#uselttvgui" name="TOCuselttvgui">Use graphical LTTV to control
  39 tracing and analyse traces</a></li>
  40 <li><a href="#uselttngtext" name="TOCuselttngtext">Use text mode LTTng to
  41 control tracing</a></li>
  42 <li><a href="#uselttvtext" name="TOCuselttvtext">Use text mode LTTV</a></li>
  43 <li><a href="#hybrid" name="TOChybrid">Tracing in "Hybrid" mode</a></li>
  44 <li><a href="#flight" name="TOCflight">Tracing in flight recorder mode</a></li>
  45 </ul>
  46
  47 <li><a href="#section3" name="TOCsection3">Adding kernel and user-space
  48 instrumentation</a>
  49 <ul>
  50 <li><a href="#kerneltp" name="TOCkerneltp">Adding kernel instrumentation</a></li>
  51 <li><a href="#usertp" name="TOCusertp">Adding userspace instrumentation</a></li>
  52 </ul>
  53
  54 <li><a href="#section4" name="TOCsection4">Creating Debian and RPM packages
  55 from LTTV</a></li>
  56 <ul>
  57 <li><a href="#pkgdebian" name="TOCpkgdebian">Create custom LTTV Debian
  58 <li><a href="#pkglttng" name="TOCpkglttng">Create custom LTTng packages</a></li>
  59 </ul>
  60
  61 <li><a href="#section5" name="TOCsection5">Examples of LTTng use in the
  62 field</a></li>
  63
  64 </ul>
  65
  66 <hr />
  67
  68 <h2><a href="#TOCintro" name="intro">Introduction</a></h2>
  69 <p>
  70 This document is made of five parts : the first one explains how
  71 to install LTTng and LTTV from sources, the second one describes the steps
  72 to follow to trace a system and view it. The third part explains
  73 briefly how to add a new trace point to the kernel and to user space
  74 applications. The fourth part explains how to create Debian or RPM
  75 packages from the LTTng and LTTV sources. The fifth and last part describes use
  76 of LTTng in the field.
  77 <p>
  78 These operations are made for installing the LTTng 0.86 tracer on a linux 2.6.X
  79 kernel. You will also find instructions for installation of LTTV 0.12.x : the
  80 Linux Trace Toolkit Viewer.
  81 To see the list of compatibilities between LTTng, ltt-control, LTTV, please
  82 refer to :
  83 <a
  84 href="http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV versions compatibility</a>
  85
  86 The ongoing work had the Linux Kernel Markers integrated in the mainline Linux
  87 kernel since Linux 2.6.24 and the Tracepoints since 2.6.28. In its current
  88 state, the lttng patchset is necessary to have the trace clocksource, the
  89 instrumentation and the LTTng high-speed data extraction mechanism added to the
  90 kernel.
  91
  92 <br>
  93 <br>
  94 <h3><a href="#TOCarch" name="arch">Supported architectures</a></h3>
  95 <br>
  96 LTTng :<br>
  97 <br>
  98 <li> x86 32/64 bits
  99 <li> PowerPC 32 and 64 bits
 100 <li> ARM (with limited timestamping precision, e.g. 1HZ. Need
 101 architecture-specific support for better precision)
 102 <li> MIPS
 103 <li> sh (partial architecture-specific instrumentation)
 104 <li> sparc64 (partial architecture-specific instrumentation)
 105 <li> s390 (partial architecture-specific instrumentation)
 106 <li> Other architectures supported without architecture-specific instrumentation
 107 and with low-resolution timestamps.<br>
 108 <br>
 109 <br>
 110 LTTV :<br>
 111 <br>
 112 <li> Intel 32/64 bits
 113 <li> PowerPC 32 and 64 bits
 114 <li> Possibly others. Takes care of endianness and type size difference between
 115 the LTTng traces and the LTTV analysis tool.
 116
 117 <hr />
 118
 119
 120 <h2><a href="#TOCsection1" name="section1">Installation from sources</a></h2>
 121 <p>
 122
 123 <h3><a href="#TOCprerequisites" name="prerequisites">Prerequisites</a></h3>
 124 <ul>
 125 <p>
 126 Tools needed to follow the package download steps :
 127
 128 <li>wget
 129 <li>bzip2
 130 <li>gzip
 131 <li>tar
 132
 133 <p>
 134 You have to install the standard development libraries and programs necessary
 135 to compile a kernel :
 136
 137 <PRE>
 138 (from Documentation/Changes in the Linux kernel tree)
 139 Gnu C                2.95.3                # gcc --version
 140 Gnu make             3.79.1                # make --version
 141 binutils             2.12                  # ld -v
 142 util-linux           2.10o                 # fdformat --version
 143 module-init-tools    0.9.10                # depmod -V
 144 </PRE>
 145
 146 <p>
 147 You might also want to have libncurses5 to have the text mode kernel
 148 configuration menu, but there are alternatives.
 149
 150 <p>
 151 Prerequisites for LTTV 0.x.x installation are :
 152
 153 <PRE>
 154 gcc 3.2 or better
 155 gtk 2.4 or better development libraries
 156   (Debian : libgtk2.0, libgtk2.0-dev)
 157   (Fedora : gtk2, gtk2-devel)
 158   note : For Fedora users : this might require at least core 3 from Fedora,
 159   or you might have to compile your own GTK2 library.
 160 glib 2.4 or better development libraries
 161   (Debian : libglib2.0-0, libglib2.0-dev)
 162   (Fedora : glib2, glib2-devel)
 163 libpopt development libraries
 164   (Debian : libpopt0, libpopt-dev)
 165   (Fedora : popt)
 166 libpango development libraries
 167   (Debian : libpango1.0, libpango1.0-dev)
 168   (Fedora : pango, pango-devel)
 169 libc6 development librairies
 170   (Debian : libc6, libc6-dev)
 171   (Fedora : glibc, glibc)
 172 </PRE>
 173 </ul>
 174
 175 <li>Reminder</li>
 176
 177 <p>
 178 See the list of compatibilities between LTTng, ltt-control and LTTV at :
 179 <a
 180 href="http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV
 181 versions compatibility</a>.
 182
 183
 184 <h3><a href="#TOCgetlttng" name="getlttng">Getting the LTTng packages</a></h3>
 185
 186 <PRE>
 187 su -
 188 mkdir /usr/src/lttng
 189 cd /usr/src/lttng
 190 (see http://ltt.polymtl.ca/lttng for package listing)
 191 wget http://ltt.polymtl.ca/lttng/patch-2.6.X-lttng-0.x.xx.tar.bz2
 192 bzip2 -cd patch-2.6.X-lttng-0.x.xx.tar.bz2 | tar xvof -
 193 </PRE>
 194
 195
 196 <h3><a href="#TOCgetlttngsrc" name="getlttngsrc">Getting LTTng kernel sources</a></h3>
 197
 198 <PRE>
 199 su -
 200 cd /usr/src
 201 wget http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.X.tar.bz2
 202 bzip2 -cd linux-2.6.X.tar.bz2 | tar xvof -
 203 cd linux-2.6.X
 204 - For LTTng 0.9.4- cat /usr/src/lttng/patch*-2.6.X-lttng-0.x.xx* | patch -p1
 205 - For LTTng 0.9.5+ apply the patches in the order specified in the series file,
 206   or use quilt
 207 cd ..
 208 mv linux-2.6.X linux-2.6.X-lttng-0.x.xx
 209 </PRE>
 210
 211
 212 <h3><a href="#TOCinstalllttng" name="installlttng">Installing a LTTng kernel</a></h3>
 213
 214 <PRE>
 215 su -
 216 cd /usr/src/linux-2.6.X-lttng-0.x.xx
 217 make menuconfig (or make xconfig or make config)
 218     Select the < Help > button if you are not familiar with kernel
 219     configuration.
 220     Items preceded by [*] means they has to be built into the kernel.
 221     Items preceded by [M] means they has to be built as modules.
 222     Items preceded by [ ] means they should be removed.
 223   go to the "General setup" section
 224     Select the following options :
 225     [*] Prompt for development and/or incomplete code/drivers
 226     [*] Activate markers
 227     [*] Activate userspace markers ABI (experimental, optional)
 228     [*] Immediate value optimization (optional)
 229     [*] Linux Trace Toolkit Next Generation (LTTng) --->
 230     <M> or <*> Compile lttng tracing probes
 231     <M> or <*> Linux Trace Toolkit High-speed Lockless Data Relay
 232     <M> or <*> Linux Trace Toolkit Lock-Protected Data Relay
 233     <M> or <*> Linux Trace Toolkit Serializer
 234     <M> or <*>   Linux Trace Toolkit Marker Control
 235     <M> or <*>     Linux Trace Toolkit Tracer
 236     [*] Align Linux Trace Toolkit Traces
 237     <M> or <*> Support logging events from userspace
 238     [*] Support trace extraction from crash dump
 239     <M> or <*> Linux Trace Toolkit Trace Controller
 240     <M> or <*> Linux Trace Toolkit State Dump
 241   Select <Exit>
 242   Select <Exit>
 243   Select <Yes>
 244 make
 245 make modules_install
 246 (if necessary, create a initrd with mkinitrd or your preferate alternative)
 247 (mkinitrd -o /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx)
 248
 249 -- on X86, X86_64
 250 make install
 251 reboot
 252 Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
 253
 254 -- on PowerPC
 255 cp vmlinux.strip /boot/vmlinux-2.6.X-lttng-0.x.xx
 256 cp System.map /boot/System.map-2.6.X-lttng-0.x.xx
 257 cp .config /boot/config-2.6.X-lttng-0.x.xx
 258 depmod -ae -F /boot/System.map-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
 259 mkinitrd /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
 260 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
 261 that comes first is the default kernel)
 262 ybin
 263 select the right entry at the yaboot prompt (see choices : tab, select : type
 264 the kernel name followed by enter)
 265 Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
 266 --
 267 </PRE>
 268
 269 <h3><a href="#TOCeditconfig" name="editconfig">Editing the system wide
 270 configuration</a></h3>
 271
 272 <p>
 273 You must activate debugfs and specify a mount point. This is typically done in
 274 fstab such that it happens at boot time.  If you have never used DebugFS before,
 275 these operation would do this for you :
 276
 277 <PRE>
 278 mkdir /mnt/debugfs
 279 cp /etc/fstab /etc/fstab.lttng.bkp
 280 echo "debugfs         /mnt/debugfs    debugfs rw              0       0"  >> /etc/fstab
 281 </PRE>
 282
 283 <p>
 284 then, rebooting or issuing the following command will activate debugfs :
 285 <PRE>
 286 mount /mnt/debugfs
 287 </PRE>
 288
 289 <p>
 290 You need to load the LTT modules to be able to control tracing from user
 291 space. This is done by issuing the following commands. Note however
 292 these commands load all LTT modules. Depending on what options you chose to
 293 compile statically, you may not need to issue all these commands.
 294
 295 <PRE>
 296 modprobe ltt-trace-control
 297 modprobe ltt-marker-control
 298 modprobe ltt-tracer
 299 modprobe ltt-serialize
 300 modprobe ltt-relay
 301 modprobe ipc-trace
 302 modprobe kernel-trace
 303 modprobe mm-trace
 304 modprobe net-trace
 305 modprobe fs-trace
 306 modprobe jbd2-trace
 307 modprobe ext4-trace
 308 modprobe syscall-trace
 309 modprobe trap-trace
 310 #if locking tracing is wanted, uncomment the following
 311 #modprobe lockdep-trace
 312 </PRE>
 313
 314 <p>
 315 If you want to have complete information about the kernel state (including all
 316 the process names), you need to load the ltt-statedump module. This is done by
 317 issuing the command :
 318
 319 <PRE>
 320 modprobe ltt-statedump
 321 </PRE>
 322 <p>
 323 You can automate at boot time loading the ltt-control module by :
 324
 325 <PRE>
 326 cp /etc/modules /etc/modules.bkp
 327 echo ltt-trace-control >> /etc/modules
 328 echo ltt-marker-control >> /etc/modules
 329 echo ltt-tracer >> /etc/modules
 330 echo ltt-serialize >> /etc/modules
 331 echo ltt-relay >> /etc/modules
 332 echo ipc-trace >> /etc/modules
 333 echo kernel-trace >> /etc/modules
 334 echo mm-trace >> /etc/modules
 335 echo net-trace >> /etc/modules
 336 echo fs-trace >> /etc/modules
 337 echo jbd2-trace >> /etc/modules
 338 echo ext4-trace >> /etc/modules
 339 echo syscall-trace >> /etc/modules
 340 echo trap-trace >> /etc/modules
 341 #if locking tracing is wanted, uncomment the following
 342 #echo lockdep-trace >> /etc/modules
 343 </PRE>
 344
 345
 346 <h3><a href="#TOCgetlttctl" name="getlttctl">Getting and installing the
 347 ltt-control package (on the traced machine)</a></h3>
 348 <p>
 349 (note : the ltt-control package contains lttd and lttctl. Although it has the
 350 same name as the ltt-control kernel module, they are *not* the same thing.)
 351
 352 <PRE>
 353 su -
 354 cd /usr/src
 355 wget http://ltt.polymtl.ca/lttng/ltt-control-0.x-xxxx2006.tar.gz
 356 gzip -cd ltt-control-0.x-xxxx2008.tar.gz | tar xvof -
 357 cd ltt-control-0.x-xxxx2006
 358 (refer to README to see the development libraries that must be installed on you
 359 system)
 360 ./configure
 361 make
 362 make install
 363 </PRE>
 364
 365 <h3><a href="#TOCuserspacetracing" name="userspacetracing">Userspace tracing</a></h3>
 366
 367 <PRE>
 368 Make sure you selected the kernel menuconfig option :
 369     <M> or <*> Support logging events from userspace
 370 And that the ltt-userspace-event kernel module is loaded if selected as a
 371 module.
 372
 373 Simple userspace tracing is available through
 374 echo "some text to record" > /mnt/debugfs/ltt/write_event
 375
 376 It will appear in the trace under event :
 377 channel : userspace
 378 event name : event
 379 </PRE>
 380
 381 <h3><a href="#TOCgetlttv" name="getlttv">Getting and installing the LTTV package
 382 (on the visualisation machine, same
 383 or different from the visualisation machine)</a></h3>
 384
 385 <PRE>
 386 su -
 387 cd /usr/src
 388 wget http://ltt.polymtl.ca/packages/lttv-0.x.xx-xxxx2008.tar.gz
 389 gzip -cd lttv-0.x.xx-xxxx2008.tar.gz | tar xvof -
 390 cd lttv-0.x.xx-xxxx2008
 391 (refer to README to see the development libraries that must be installed on your
 392 system)
 393 ./configure
 394 make
 395 make install
 396 </PRE>
 397
 398 <hr />
 399
 400
 401 <h2><a href="#TOCsection2" name="section2">Using LTTng and LTTV</a></h2>
 402
 403 <li><b>IMPORTANT : Arm Linux Kernel Markers after each boot before tracing</b></li>
 404 <PRE>
 405 ltt-armall
 406 </PRE>
 407
 408 <h3><a href="#TOCuselttvgui" name="uselttvgui">Use graphical LTTV to control
 409 tracing and analyse traces</a></h3>
 410 <PRE>
 411 lttv-gui (or /usr/local/bin/lttv-gui)
 412   - Spot the "Tracing Control" icon : click on it
 413       (it's a traffic light icon)
 414     - enter the root password
 415     - click "start"
 416     - click "stop"
 417     - Yes
 418       * You should now see a trace
 419 </PRE>
 420
 421 <h3><a href="#TOCuselttngtext" name="uselttngtext">Use text mode LTTng to control tracing</a></h3>
 422 <PRE>
 423 The tracing can be controlled from a terminal by using the lttctl command (as
 424 root).
 425
 426 Start tracing :
 427
 428 lttctl -C -w /tmp/trace1 trace1
 429
 430 Stop tracing and destroy trace channels :
 431
 432 lttctl -D trace1
 433
 434 see lttctl --help for details.
 435 </PRE>
 436 <p>
 437 (note : to see if the buffers has been filled, look at the dmesg output after
 438 lttctl -R or after stopping tracing from the GUI, it will show an event lost
 439 count. If it is the case, try using larger buffers. See lttctl --help to learn
 440 how. lttv now also shows event lost messages in the console when loading a trace
 441 with missing events or lost subbuffers.)
 442
 443 <h3><a href="#TOCuselttvtext" name="uselttvtext">Use text mode LTTV</a></h3>
 444 <p>
 445 Feel free to look in /usr/local/lib/lttv/plugins to see all the text and
 446 graphical plugins available.
 447 <p>
 448 For example, a simple trace dump in text format is available with :
 449 <PRE>
 450 lttv -m textDump -t /tmp/trace
 451 </PRE>
 452 <p>
 453 See lttv -m textDump --help for detailed command line options of textDump.
 454 <p>
 455 It is, in the current state of the project, very useful to use "grep" on the
 456 text output to filter by specific event fields. You can later copy the timestamp
 457 of the events to the clipboard and paste them in the GUI by clicking on the
 458 bottom right label "Current time". Support for this type of filtering should
 459 be added to the filter module soon.
 460
 461 <h3><a href="#TOChybrid" name="hybrid">Tracing in "Hybrid" mode</a></h3>
 462 <p>
 463 Starting from LTTng 0.5.105 and ltt-control 0.20, a new mode can be used :
 464 hybrid. It can be especially useful when studying big workloads on a long period
 465 of time.
 466 <p>
 467 When using this mode, the most important, low rate control information will be
 468 recorded during all the trace by lttd (i.e. process creation/exit). The high
 469 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
 470 flight recorder buffer (now named flight-channelname_X).
 471 <p>
 472 The following lttctl commands take an hybrid trace :
 473 <p>
 474 Create trace channel, start lttd on normal channels, start tracing:
 475 <PRE>
 476 lttctl -C -w /tmp/trace2 -o channel.kernel.overwrite=1 trace2
 477 </PRE>
 478 <p>
 479 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
 480 <PRE>
 481 lttctl -D -w /tmp/trace2 trace2
 482 </PRE>
 483 <p>
 484 Each "overwrite" channel is flight recorder channel.
 485
 486
 487 <h3><a href="#TOCflight" name="flight">Tracing in flight recorder mode</a></h3>
 488 <li>Flight recorder mode</li>
 489 <p>
 490 The flight recorder mode writes data into overwritten buffers for all channels,
 491 including control channels, except for the facilities tracefiles. It consists of
 492 setting all channels to "overwrite".
 493 <p>
 494 The following lttctl commands take a flight recorder trace :
 495 <PRE>
 496 lttctl -C -w /tmp/trace3 -o channel.all.overwrite=1 trace3
 497 ...
 498 lttctl -D -w /tmp/trace3 trace3
 499 </PRE>
 500
 501 <hr />
 502
 503
 504 <h2><a href="#TOCsection3" name="section3">Adding new instrumentations with the
 505 markers</a></h2>
 506 <p>
 507
 508 <h3><a href="#TOCkerneltp" name="kerneltp">Adding kernel
 509 instrumentation</a></h3>
 510
 511 <p>
 512 See <a
 513 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>
 514 and <a
 515 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
 516 tree.
 517 <p>
 518 Also see <a
 519 href="http://git.kernel.org/?p=linux/kernel/git/compudj/linux-2.6-lttng.git;a=tree;f=ltt/probes">ltt/probes/</a>
 520 for LTTng probe examples.
 521
 522 <h3><a href="#TOCusertp" name="usertp">Adding userspace instrumentation</a></h3>
 523
 524 Add new events to userspace programs with
 525 <a href="http://ltt.polymtl.ca/packages/">userspace markers packages</a>.
 526 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
 527 allows inserting markers in executables and libraries, currently only on x86_32
 528 and x86_64.
 529 See <a
 530 href="http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2">markers-userspace-0.5.tar.bz2</a> or more recent.
 531
 532 <p>
 533 Note that a new design document for a 3rd generation of tracepoint/marker-based
 534 userspace tracing is available at <a
 535 href="http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/ust.html">LTTng User-space Tracing
 536 Design</a>. This new infrastructure is not yet implemented.
 537
 538 <p>
 539 The easy quick-and-dirty way to perform userspace tracing is currently to write
 540 an string to /mnt/debugfs/ltt/write_event. See <a
 541 href="#userspacetracing">Userspace tracing</a> in the
 542 installation for sources section of this document.
 543
 544 <hr />
 545
 546 <h2><a href="#TOCsection4" name="section4">Creating Debian or RPM packages</a></h2>
 547 <p>
 548
 549 <h3><a href="#TOCpkgdebian" name="pkgdebian">Create custom LTTV Debian packages</a></h3>
 550
 551 <PRE>
 552 Use : dpkg-buildpackage -rfakeroot
 553 </PRE>
 554 <p>
 555 You should then have your LTTV .deb files created for your architecture.
 556
 557 <h3><a href="#TOCpkglttng" name="pkglttng">Create custom LTTng packages</a></h3>
 558 <p>
 559 For building LTTng Debian packages :
 560 get the build tree with patches applies as explained in section 2.
 561
 562 <PRE>
 563 make menuconfig (or xconfig or config) (customize your configuration)
 564 make-kpkg kernel_image
 565 </PRE>
 566 <p>
 567 You will then see your freshly created .deb in /usr/src. Install it with
 568 <PRE>
 569 dpkg -i /usr/src/(image-name).deb
 570 </PRE>
 571 <p>
 572 Then, follow the section "Editing the system wide configuration" in section 2.
 573
 574 <hr />
 575
 576 <h2><a href="#TOCsection5" name="section5">Examples of LTTng use in the field</a></h2>
 577 <p>
 578 A few examples of successful LTTng users :
 579
 580 <ul>
 581 <li> Google are deploying LTTng on their servers. They want to use it to
 582   monitor their production servers (with flight recorder mode tracing)
 583   and to help them solve hard to reproduce problems. They have had
 584   success with such tracing approach to fix "rare disk delay" issues and
 585   VM-related issues presented in this article :
 586 <ul>
 587   <li> <a href="http://ltt.polymtl.ca/papers/bligh-Reprint.pdf">Linux Kernel
 588 Debugging on Google-sized clusters at Ottawa Linux
 589     Symposium 2007</a>
 590 </ul>
 591 <li> IBM Research have had problems with Commercial Scale-out applications,
 592   which are being an increasing trend to split large server workloads.
 593   They used LTTng successfully to solve a distributed filesystem-related
 594   issue. It's presented in the same paper above.
 595
 596 <li> Autodesk, in the development of their next-generation of Linux
 597   audio/video edition applications, used LTTng extensively to solve
 598   soft real-time issues they had. Also presented in the same paper.
 599
 600 <li> Wind River included LTTng in their Linux distribution so their
 601   clients, already familiar to Wind River own tracing solution in
 602   VxWorks, car have the same kind of feature they have relied on for a
 603   long time.
 604
 605 <li> Montavista have integrated LTTng in their distribution for the same
 606   reasons. It's used by Sony amongst others.
 607
 608 <li> SuSE are currently integrating LTTng in their next SLES distribution,
 609   because their clients asking for solutions which supports a kernel
 610   closer to real-time need such tools to debug their problems.
 611
 612 <li> A project between Ericsson, the Canadian Defense, NSERC and various
 613   universities is just starting. It aims at monitoring and debugging
 614   multi-core systems and provide automated and help user system behavior
 615   analysis.
 616
 617 <li> Siemens have been using LTTng internally for quite some time now.
 618 </ul>
 619   </body>
 620 </html>