trunk/lttv/QUICKSTART.html

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
   2 <html>
   3 <head>
   4   <title>Linux Trace Toolkit Next Generation User Documentation</title>
   5 </head>
   6   <body>
   7
   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 The lttng patch is necessary to have the tracing hooks in the kernel.
  86
  87 <br>
  88 <br>
  89 <h3><a href="#TOCarch" name="arch">Supported architectures</a></h3>
  90 <br>
  91 LTTng :<br>
  92 <br>
  93 <li> x86 32/64 bits
  94 <li> PowerPC 32 and 64 bits
  95 <li> ARM (with limited timestamping precision, e.g. 1HZ. Need
  96 architecture-specific support for better precision)
  97 <li> MIPS
  98 <li> sh (partial architecture-specific instrumentation)
  99 <li> sparc64 (partial architecture-specific instrumentation)
 100 <li> s390 (partial architecture-specific instrumentation)
 101 <li> Other architectures supported without architecture-specific instrumentation
 102 and with low-resolution timestamps.<br>
 103 <br>
 104 <br>
 105 LTTV :<br>
 106 <br>
 107 <li> Intel 32/64 bits
 108 <li> PowerPC 32 and 64 bits
 109 <li> Possibly others. Takes care of endianness and type size difference between
 110 the LTTng traces and the LTTV analysis tool.
 111
 112 <hr />
 113
 114
 115 <h2><a href="#TOCsection1" name="section1">Installation from sources</a></h2>
 116 <p>
 117
 118 <h3><a href="#TOCprerequisites" name="prerequisites">Prerequisites</a></h3>
 119 <ul>
 120 <p>
 121 Tools needed to follow the package download steps :
 122
 123 <li>wget
 124 <li>bzip2
 125 <li>gzip
 126 <li>tar
 127
 128 <p>
 129 You have to install the standard development libraries and programs necessary
 130 to compile a kernel :
 131
 132 <PRE>
 133 (from Documentation/Changes in the Linux kernel tree)
 134 Gnu C                2.95.3                # gcc --version
 135 Gnu make             3.79.1                # make --version
 136 binutils             2.12                  # ld -v
 137 util-linux           2.10o                 # fdformat --version
 138 module-init-tools    0.9.10                # depmod -V
 139 </PRE>
 140
 141 <p>
 142 You might also want to have libncurses5 to have the text mode kernel
 143 configuration menu, but there are alternatives.
 144
 145 <p>
 146 Prerequisites for LTTV 0.x.x installation are :
 147
 148 <PRE>
 149 gcc 3.2 or better
 150 gtk 2.4 or better development libraries
 151   (Debian : libgtk2.0, libgtk2.0-dev)
 152   (Fedora : gtk2, gtk2-devel)
 153   note : For Fedora users : this might require at least core 3 from Fedora,
 154   or you might have to compile your own GTK2 library.
 155 glib 2.4 or better development libraries
 156   (Debian : libglib2.0-0, libglib2.0-dev)
 157   (Fedora : glib2, glib2-devel)
 158 libpopt development libraries
 159   (Debian : libpopt0, libpopt-dev)
 160   (Fedora : popt)
 161 libpango development libraries
 162   (Debian : libpango1.0, libpango1.0-dev)
 163   (Fedora : pango, pango-devel)
 164 libc6 development librairies
 165   (Debian : libc6, libc6-dev)
 166   (Fedora : glibc, glibc)
 167 </PRE>
 168 </ul>
 169
 170 <li>Reminder</li>
 171
 172 <p>
 173 See the list of compatibilities between LTTng, ltt-control and LTTV at :
 174 <a
 175 href="http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV
 176 versions compatibility</a>.
 177
 178
 179 <h3><a href="#TOCgetlttng" name="getlttng">Getting the LTTng packages</a></h3>
 180
 181 <PRE>
 182 su -
 183 mkdir /usr/src/lttng
 184 cd /usr/src/lttng
 185 (see http://ltt.polymtl.ca/lttng for package listing)
 186 wget http://ltt.polymtl.ca/lttng/patch-2.6.X-lttng-0.x.xx.tar.bz2
 187 bzip2 -cd patch-2.6.X-lttng-0.x.xx.tar.bz2 | tar xvof -
 188 </PRE>
 189
 190
 191 <h3><a href="#TOCgetlttngsrc" name="getlttngsrc">Getting LTTng kernel sources</a></h3>
 192
 193 <PRE>
 194 su -
 195 cd /usr/src
 196 wget http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.X.tar.bz2
 197 bzip2 -cd linux-2.6.X.tar.bz2 | tar xvof -
 198 cd linux-2.6.X
 199 - For LTTng 0.9.4- cat /usr/src/lttng/patch*-2.6.X-lttng-0.x.xx* | patch -p1
 200 - For LTTng 0.9.5+ apply the patches in the order specified in the series file,
 201   or use quilt
 202 cd ..
 203 mv linux-2.6.X linux-2.6.X-lttng-0.x.xx
 204 </PRE>
 205
 206
 207 <h3><a href="#TOCinstalllttng" name="installlttng">Installing a LTTng kernel</a></h3>
 208
 209 <PRE>
 210 su -
 211 cd /usr/src/linux-2.6.X-lttng-0.x.xx
 212 make menuconfig (or make xconfig or make config)
 213     Select the < Help > button if you are not familiar with kernel
 214     configuration.
 215     Items preceded by [*] means they has to be built into the kernel.
 216     Items preceded by [M] means they has to be built as modules.
 217     Items preceded by [ ] means they should be removed.
 218   go to the "General setup" section
 219     Select the following options :
 220     [*] Prompt for development and/or incomplete code/drivers
 221     [*] Activate markers
 222     [*] Activate userspace markers ABI (experimental, optional)
 223     [*] Immediate value optimization (optional)
 224     [*] Linux Trace Toolkit Next Generation (LTTng) --->
 225     <M> or <*> Compile lttng tracing probes
 226     <M> or <*> Linux Trace Toolkit High-speed Lockless Data Relay
 227     <M> or <*> Linux Trace Toolkit Lock-Protected Data Relay
 228     <M> or <*> Linux Trace Toolkit Serializer
 229     <M> or <*>   Linux Trace Toolkit Marker Control
 230     <M> or <*>     Linux Trace Toolkit Tracer
 231     [*] Align Linux Trace Toolkit Traces
 232     <M> or <*> Support logging events from userspace
 233     [*] Support trace extraction from crash dump
 234     <M> or <*> Linux Trace Toolkit Trace Controller
 235     <M> or <*> Linux Trace Toolkit State Dump
 236   Select <Exit>
 237   Select <Exit>
 238   Select <Yes>
 239 make
 240 make modules_install
 241 (if necessary, create a initrd with mkinitrd or your preferate alternative)
 242 (mkinitrd -o /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx)
 243
 244 -- on X86, X86_64
 245 make install
 246 reboot
 247 Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
 248
 249 -- on PowerPC
 250 cp vmlinux.strip /boot/vmlinux-2.6.X-lttng-0.x.xx
 251 cp System.map /boot/System.map-2.6.X-lttng-0.x.xx
 252 cp .config /boot/config-2.6.X-lttng-0.x.xx
 253 depmod -ae -F /boot/System.map-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
 254 mkinitrd /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
 255 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
 256 that comes first is the default kernel)
 257 ybin
 258 select the right entry at the yaboot prompt (see choices : tab, select : type
 259 the kernel name followed by enter)
 260 Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
 261 --
 262 </PRE>
 263
 264 <h3><a href="#TOCeditconfig" name="editconfig">Editing the system wide
 265 configuration</a></h3>
 266
 267 <p>
 268 You must activate debugfs and specify a mount point. This is typically done in
 269 fstab such that it happens at boot time.  If you have never used DebugFS before,
 270 these operation would do this for you :
 271
 272 <PRE>
 273 mkdir /mnt/debugfs
 274 cp /etc/fstab /etc/fstab.lttng.bkp
 275 echo "debugfs         /mnt/debugfs    debugfs rw              0       0"  >> /etc/fstab
 276 </PRE>
 277
 278 <p>
 279 then, rebooting or issuing the following command will activate debugfs :
 280 <PRE>
 281 mount /mnt/debugfs
 282 </PRE>
 283
 284 <p>
 285 You need to load the LTT modules to be able to control tracing from user
 286 space. This is done by issuing the following commands. Note however
 287 these commands load all LTT modules. Depending on what options you chose to
 288 compile statically, you may not need to issue all these commands.
 289
 290 <PRE>
 291 modprobe ltt-trace-control
 292 modprobe ltt-marker-control
 293 modprobe ltt-tracer
 294 modprobe ltt-serialize
 295 modprobe ltt-relay
 296 modprobe ipc-trace
 297 modprobe kernel-trace
 298 modprobe mm-trace
 299 modprobe net-trace
 300 modprobe fs-trace
 301 modprobe jbd2-trace
 302 modprobe ext4-trace
 303 modprobe syscall-trace
 304 modprobe trap-trace
 305 #if locking tracing is wanted, uncomment the following
 306 #modprobe lockdep-trace
 307 </PRE>
 308
 309 <p>
 310 If you want to have complete information about the kernel state (including all
 311 the process names), you need to load the ltt-statedump module. This is done by
 312 issuing the command :
 313
 314 <PRE>
 315 modprobe ltt-statedump
 316 </PRE>
 317 <p>
 318 You can automate at boot time loading the ltt-control module by :
 319
 320 <PRE>
 321 cp /etc/modules /etc/modules.bkp
 322 echo ltt-trace-control >> /etc/modules
 323 echo ltt-marker-control >> /etc/modules
 324 echo ltt-tracer >> /etc/modules
 325 echo ltt-serialize >> /etc/modules
 326 echo ltt-relay >> /etc/modules
 327 echo ipc-trace >> /etc/modules
 328 echo kernel-trace >> /etc/modules
 329 echo mm-trace >> /etc/modules
 330 echo net-trace >> /etc/modules
 331 echo fs-trace >> /etc/modules
 332 echo jbd2-trace >> /etc/modules
 333 echo ext4-trace >> /etc/modules
 334 echo syscall-trace >> /etc/modules
 335 echo trap-trace >> /etc/modules
 336 #if locking tracing is wanted, uncomment the following
 337 #echo lockdep-trace >> /etc/modules
 338 </PRE>
 339
 340
 341 <h3><a href="#TOCgetlttctl" name="getlttctl">Getting and installing the
 342 ltt-control package (on the traced machine)</a></h3>
 343 <p>
 344 (note : the ltt-control package contains lttd and lttctl. Although it has the
 345 same name as the ltt-control kernel module, they are *not* the same thing.)
 346
 347 <PRE>
 348 su -
 349 cd /usr/src
 350 wget http://ltt.polymtl.ca/lttng/ltt-control-0.x-xxxx2006.tar.gz
 351 gzip -cd ltt-control-0.x-xxxx2008.tar.gz | tar xvof -
 352 cd ltt-control-0.x-xxxx2006
 353 (refer to README to see the development libraries that must be installed on you
 354 system)
 355 ./configure
 356 make
 357 make install
 358 </PRE>
 359
 360 <h3><a href="#TOCuserspacetracing" name="userspacetracing">Userspace tracing</a></h3>
 361
 362 <PRE>
 363 Make sure you selected the kernel menuconfig option :
 364     <M> or <*> Support logging events from userspace
 365 And that the ltt-userspace-event kernel module is loaded if selected as a
 366 module.
 367
 368 Simple userspace tracing is available through
 369 echo "some text to record" > /mnt/debugfs/ltt/write_event
 370
 371 It will appear in the trace under event :
 372 channel : userspace
 373 event name : event
 374 </PRE>
 375
 376 <h3><a href="#TOCgetlttv" name="getlttv">Getting and installing the LTTV package
 377 (on the visualisation machine, same
 378 or different from the visualisation machine)</a></h3>
 379
 380 <PRE>
 381 su -
 382 cd /usr/src
 383 wget http://ltt.polymtl.ca/packages/lttv-0.x.xx-xxxx2008.tar.gz
 384 gzip -cd lttv-0.x.xx-xxxx2008.tar.gz | tar xvof -
 385 cd lttv-0.x.xx-xxxx2008
 386 (refer to README to see the development libraries that must be installed on your
 387 system)
 388 ./configure
 389 make
 390 make install
 391 </PRE>
 392
 393 <hr />
 394
 395
 396 <h2><a href="#TOCsection2" name="section2">Using LTTng and LTTV</a></h2>
 397
 398 <li><b>IMPORTANT : Arm Linux Kernel Markers after each boot before tracing</b></li>
 399 <PRE>
 400 ltt-armall
 401 </PRE>
 402
 403 <h3><a href="#TOCuselttvgui" name="uselttvgui">Use graphical LTTV to control
 404 tracing and analyse traces</a></h3>
 405 <PRE>
 406 lttv-gui (or /usr/local/bin/lttv-gui)
 407   - Spot the "Tracing Control" icon : click on it
 408       (it's a traffic light icon)
 409     - enter the root password
 410     - click "start"
 411     - click "stop"
 412     - Yes
 413       * You should now see a trace
 414 </PRE>
 415
 416 <h3><a href="#TOCuselttngtext" name="uselttngtext">Use text mode LTTng to control tracing</a></h3>
 417 <PRE>
 418 The tracing can be controlled from a terminal by using the lttctl command (as
 419 root).
 420
 421 Start tracing :
 422
 423 lttctl -C -w /tmp/trace1 trace1
 424
 425 Stop tracing and destroy trace channels :
 426
 427 lttctl -D trace1
 428
 429 see lttctl --help for details.
 430 </PRE>
 431 <p>
 432 (note : to see if the buffers has been filled, look at the dmesg output after
 433 lttctl -R or after stopping tracing from the GUI, it will show an event lost
 434 count. If it is the case, try using larger buffers. See lttctl --help to learn
 435 how. lttv now also shows event lost messages in the console when loading a trace
 436 with missing events or lost subbuffers.)
 437
 438 <h3><a href="#TOCuselttvtext" name="uselttvtext">Use text mode LTTV</a></h3>
 439 <p>
 440 Feel free to look in /usr/local/lib/lttv/plugins to see all the text and
 441 graphical plugins available.
 442 <p>
 443 For example, a simple trace dump in text format is available with :
 444 <PRE>
 445 lttv -m textDump -t /tmp/trace
 446 </PRE>
 447 <p>
 448 See lttv -m textDump --help for detailed command line options of textDump.
 449 <p>
 450 It is, in the current state of the project, very useful to use "grep" on the
 451 text output to filter by specific event fields. You can later copy the timestamp
 452 of the events to the clipboard and paste them in the GUI by clicking on the
 453 bottom right label "Current time". Support for this type of filtering should
 454 be added to the filter module soon.
 455
 456 <h3><a href="#TOChybrid" name="hybrid">Tracing in "Hybrid" mode</a></h3>
 457 <p>
 458 Starting from LTTng 0.5.105 and ltt-control 0.20, a new mode can be used :
 459 hybrid. It can be especially useful when studying big workloads on a long period
 460 of time.
 461 <p>
 462 When using this mode, the most important, low rate control information will be
 463 recorded during all the trace by lttd (i.e. process creation/exit). The high
 464 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
 465 flight recorder buffer (now named flight-channelname_X).
 466 <p>
 467 The following lttctl commands take an hybrid trace :
 468 <p>
 469 Create trace channel, start lttd on normal channels, start tracing:
 470 <PRE>
 471 lttctl -C -w /tmp/trace2 -o channel.kernel.overwrite=1 trace2
 472 </PRE>
 473 <p>
 474 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
 475 <PRE>
 476 lttctl -D -w /tmp/trace2 trace2
 477 </PRE>
 478 <p>
 479 Each "overwrite" channel is flight recorder channel.
 480
 481
 482 <h3><a href="#TOCflight" name="flight">Tracing in flight recorder mode</a></h3>
 483 <li>Flight recorder mode</li>
 484 <p>
 485 The flight recorder mode writes data into overwritten buffers for all channels,
 486 including control channels, except for the facilities tracefiles. It consists of
 487 setting all channels to "overwrite".
 488 <p>
 489 The following lttctl commands take a flight recorder trace :
 490 <PRE>
 491 lttctl -C -w /tmp/trace3 -o channel.all.overwrite=1 trace3
 492 ...
 493 lttctl -D -w /tmp/trace3 trace3
 494 </PRE>
 495
 496 <hr />
 497
 498
 499 <h2><a href="#TOCsection3" name="section3">Adding new instrumentations with the
 500 markers</a></h2>
 501 <p>
 502
 503 <h3><a href="#TOCkerneltp" name="kerneltp">Adding kernel
 504 instrumentation</a></h3>
 505
 506 <p>
 507 See <a
 508 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>
 509 and <a
 510 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
 511 tree.
 512 <p>
 513 Also see <a
 514 href="http://git.kernel.org/?p=linux/kernel/git/compudj/linux-2.6-lttng.git;a=tree;f=ltt/probes">ltt/probes/</a>
 515 for LTTng probe examples.
 516
 517 <h3><a href="#TOCusertp" name="usertp">Adding userspace instrumentation</a></h3>
 518
 519 Add new events to userspace programs with
 520 <a href="http://ltt.polymtl.ca/packages/">userspace markers packages</a>.
 521 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
 522 allows inserting markers in executables and libraries, currently only on x86_32
 523 and x86_64.
 524 See <a
 525 href="http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2">markers-userspace-0.5.tar.bz2</a> or more recent.
 526
 527 <p>
 528 Note that a new design document for a 3rd generation of tracepoint/marker-based
 529 userspace tracing is available at <a
 530 href="http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/ust.html">LTTng User-space Tracing
 531 Design</a>. This new infrastructure is not yet implemented.
 532
 533 <p>
 534 The easy quick-and-dirty way to perform userspace tracing is currently to write
 535 an string to /mnt/debugfs/ltt/write_event. See <a
 536 href="#userspacetracing">Userspace tracing</a> in the
 537 installation for sources section of this document.
 538
 539 <hr />
 540
 541 <h2><a href="#TOCsection4" name="section4">Creating Debian or RPM packages</a></h2>
 542 <p>
 543
 544 <h3><a href="#TOCpkgdebian" name="pkgdebian">Create custom LTTV Debian packages</a></h3>
 545
 546 <PRE>
 547 Use : dpkg-buildpackage -rfakeroot
 548 </PRE>
 549 <p>
 550 You should then have your LTTV .deb files created for your architecture.
 551
 552 <h3><a href="#TOCpkglttng" name="pkglttng">Create custom LTTng packages</a></h3>
 553 <p>
 554 For building LTTng Debian packages :
 555 get the build tree with patches applies as explained in section 2.
 556
 557 <PRE>
 558 make menuconfig (or xconfig or config) (customize your configuration)
 559 make-kpkg kernel_image
 560 </PRE>
 561 <p>
 562 You will then see your freshly created .deb in /usr/src. Install it with
 563 <PRE>
 564 dpkg -i /usr/src/(image-name).deb
 565 </PRE>
 566 <p>
 567 Then, follow the section "Editing the system wide configuration" in section 2.
 568
 569 <hr />
 570
 571 <h2><a href="#TOCsection5" name="section5">Examples of LTTng use in the field</a></h2>
 572 <p>
 573 A few examples of successful LTTng users :
 574
 575 <ul>
 576 <li> Google are deploying LTTng on their servers. They want to use it to
 577   monitor their production servers (with flight recorder mode tracing)
 578   and to help them solve hard to reproduce problems. They have had
 579   success with such tracing approach to fix "rare disk delay" issues and
 580   VM-related issues presented in this article :
 581 <ul>
 582   <li> <a href="http://ltt.polymtl.ca/papers/bligh-Reprint.pdf">Linux Kernel
 583 Debugging on Google-sized clusters at Ottawa Linux
 584     Symposium 2007</a>
 585 </ul>
 586 <li> IBM Research have had problems with Commercial Scale-out applications,
 587   which are being an increasing trend to split large server workloads.
 588   They used LTTng successfully to solve a distributed filesystem-related
 589   issue. It's presented in the same paper above.
 590
 591 <li> Autodesk, in the development of their next-generation of Linux
 592   audio/video edition applications, used LTTng extensively to solve
 593   soft real-time issues they had. Also presented in the same paper.
 594
 595 <li> Wind River included LTTng in their Linux distribution so their
 596   clients, already familiar to Wind River own tracing solution in
 597   VxWorks, car have the same kind of feature they have relied on for a
 598   long time.
 599
 600 <li> Montavista have integrated LTTng in their distribution for the same
 601   reasons. It's used by Sony amongst others.
 602
 603 <li> SuSE are currently integrating LTTng in their next SLES distribution,
 604   because their clients asking for solutions which supports a kernel
 605   closer to real-time need such tools to debug their problems.
 606
 607 <li> A project between Ericsson, the Canadian Defense, NSERC and various
 608   universities is just starting. It aims at monitoring and debugging
 609   multi-core systems and provide automated and help user system behavior
 610   analysis.
 611
 612 <li> Siemens have been using LTTng internally for quite some time now.
 613 </ul>
 614   </body>
 615 </html>