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   4   <title>Linux Trace Toolkit Next Generation Manual</title>
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   7
   8 <h1>Linux Trace Toolkit Next Generation Manual</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 </ul>
  62
  63 <hr />
  64
  65 <h2><a href="#TOCintro" name="intro">Introduction</a></h2>
  66 <p>
  67 This document is made of five parts : the first one explains how
  68 to install LTTng and LTTV from sources, the second one describes the steps
  69 to follow to trace a system and view it. The third part explains
  70 briefly how to add a new trace point to the kernel and to user space
  71 applications. The fourth and last part explains how to create Debian or RPM
  72 packages from the LTTng and LTTV sources.
  73 <p>
  74 These operations are made for installing the LTTng 0.86 tracer on a linux 2.6.X
  75 kernel. You will also find instructions for installation of LTTV 0.12.x : the
  76 Linux Trace Toolkit Viewer.
  77 To see the list of compatibilities between LTTng, ltt-control, LTTV, please
  78 refer to :
  79 <a
  80 href="http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV versions compatibility</a>
  81
  82 The ongoing work had the Linux Kernel Markers integrated in the mainline Linux
  83 kernel since Linux 2.6.24 and the Tracepoints since 2.6.28. In its current
  84 state, the lttng patchset is necessary to have the trace clocksource, the
  85 instrumentation and the LTTng high-speed data extraction mechanism added to the
  86 kernel.
  87
  88 <br>
  89 <br>
  90 <h3><a href="#TOCarch" name="arch">Supported architectures</a></h3>
  91 <br>
  92 LTTng :<br>
  93 <br>
  94 <li> x86 32/64 bits
  95 <li> PowerPC 32 and 64 bits
  96 <li> ARM (with limited timestamping precision, e.g. 1HZ. Need
  97 architecture-specific support for better precision)
  98 <li> MIPS
  99 <li> sh (partial architecture-specific instrumentation)
 100 <li> sparc64 (partial architecture-specific instrumentation)
 101 <li> s390 (partial architecture-specific instrumentation)
 102 <li> Other architectures supported without architecture-specific instrumentation
 103 and with low-resolution timestamps.<br>
 104 <br>
 105 <br>
 106 LTTV :<br>
 107 <br>
 108 <li> Intel 32/64 bits
 109 <li> PowerPC 32 and 64 bits
 110 <li> Possibly others. Takes care of endianness and type size difference between
 111 the LTTng traces and the LTTV analysis tool.
 112
 113 <hr />
 114
 115
 116 <h2><a href="#TOCsection1" name="section1">Installation from sources</a></h2>
 117 <p>
 118
 119 <h3><a href="#TOCprerequisites" name="prerequisites">Prerequisites</a></h3>
 120 <ul>
 121 <p>
 122 Tools needed to follow the package download steps :
 123
 124 <li>wget
 125 <li>bzip2
 126 <li>gzip
 127 <li>tar
 128
 129 <p>
 130 You have to install the standard development libraries and programs necessary
 131 to compile a kernel :
 132
 133 <PRE>
 134 (from Documentation/Changes in the Linux kernel tree)
 135 Gnu C                2.95.3                # gcc --version
 136 Gnu make             3.79.1                # make --version
 137 binutils             2.12                  # ld -v
 138 util-linux           2.10o                 # fdformat --version
 139 module-init-tools    0.9.10                # depmod -V
 140 </PRE>
 141
 142 <p>
 143 You might also want to have libncurses5 to have the text mode kernel
 144 configuration menu, but there are alternatives.
 145
 146 <p>
 147 Prerequisites for LTTV 0.x.x installation are :
 148
 149 <PRE>
 150 gcc 3.2 or better
 151 gtk 2.4 or better development libraries
 152   (Debian : libgtk2.0, libgtk2.0-dev)
 153   (Fedora : gtk2, gtk2-devel)
 154   note : For Fedora users : this might require at least core 3 from Fedora,
 155   or you might have to compile your own GTK2 library.
 156 glib 2.4 or better development libraries
 157   (Debian : libglib2.0-0, libglib2.0-dev)
 158   (Fedora : glib2, glib2-devel)
 159 libpopt development libraries
 160   (Debian : libpopt0, libpopt-dev)
 161   (Fedora : popt)
 162 libpango development libraries
 163   (Debian : libpango1.0, libpango1.0-dev)
 164   (Fedora : pango, pango-devel)
 165 libc6 development librairies
 166   (Debian : libc6, libc6-dev)
 167   (Fedora : glibc, glibc)
 168 </PRE>
 169 </ul>
 170
 171 <li>Reminder</li>
 172
 173 <p>
 174 See the list of compatibilities between LTTng, ltt-control and LTTV at :
 175 <a
 176 href="http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV
 177 versions compatibility</a>.
 178
 179
 180 <h3><a href="#TOCgetlttng" name="getlttng">Getting the LTTng packages</a></h3>
 181
 182 <PRE>
 183 su -
 184 mkdir /usr/src/lttng
 185 cd /usr/src/lttng
 186 (see http://ltt.polymtl.ca/lttng for package listing)
 187 wget http://ltt.polymtl.ca/lttng/patch-2.6.X-lttng-0.x.xx.tar.bz2
 188 bzip2 -cd patch-2.6.X-lttng-0.x.xx.tar.bz2 | tar xvof -
 189 </PRE>
 190
 191
 192 <h3><a href="#TOCgetlttngsrc" name="getlttngsrc">Getting LTTng kernel sources</a></h3>
 193
 194 <PRE>
 195 su -
 196 cd /usr/src
 197 wget http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.X.tar.bz2
 198 bzip2 -cd linux-2.6.X.tar.bz2 | tar xvof -
 199 cd linux-2.6.X
 200 - For LTTng 0.9.4- cat /usr/src/lttng/patch*-2.6.X-lttng-0.x.xx* | patch -p1
 201 - For LTTng 0.9.5+ apply the patches in the order specified in the series file,
 202   or use quilt
 203 cd ..
 204 mv linux-2.6.X linux-2.6.X-lttng-0.x.xx
 205 </PRE>
 206
 207
 208 <h3><a href="#TOCinstalllttng" name="installlttng">Installing a LTTng kernel</a></h3>
 209
 210 <PRE>
 211 su -
 212 cd /usr/src/linux-2.6.X-lttng-0.x.xx
 213 make menuconfig (or make xconfig or make config)
 214     Select the < Help > button if you are not familiar with kernel
 215     configuration.
 216     Items preceded by [*] means they has to be built into the kernel.
 217     Items preceded by [M] means they has to be built as modules.
 218     Items preceded by [ ] means they should be removed.
 219   go to the "General setup" section
 220     Select the following options :
 221     [*] Prompt for development and/or incomplete code/drivers
 222     [*] Activate markers
 223     [*] Activate userspace markers ABI (experimental, optional)
 224     [*] Immediate value optimization (optional)
 225     [*] Linux Trace Toolkit Next Generation (LTTng) --->
 226     <M> or <*> Compile lttng tracing probes
 227     <M> or <*> Linux Trace Toolkit High-speed Lockless Data Relay
 228     <M> or <*> Linux Trace Toolkit Lock-Protected Data Relay
 229     <M> or <*> Linux Trace Toolkit Serializer
 230     <M> or <*>   Linux Trace Toolkit Marker Control
 231     <M> or <*>     Linux Trace Toolkit Tracer
 232     [*] Align Linux Trace Toolkit Traces
 233     <M> or <*> Support logging events from userspace
 234     [*] Support trace extraction from crash dump
 235     <M> or <*> Linux Trace Toolkit Trace Controller
 236     <M> or <*> Linux Trace Toolkit State Dump
 237   Select <Exit>
 238   Select <Exit>
 239   Select <Yes>
 240 make
 241 make modules_install
 242 (if necessary, create a initrd with mkinitrd or your preferate alternative)
 243 (mkinitrd -o /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx)
 244
 245 -- on X86, X86_64
 246 make install
 247 reboot
 248 Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
 249
 250 -- on PowerPC
 251 cp vmlinux.strip /boot/vmlinux-2.6.X-lttng-0.x.xx
 252 cp System.map /boot/System.map-2.6.X-lttng-0.x.xx
 253 cp .config /boot/config-2.6.X-lttng-0.x.xx
 254 depmod -ae -F /boot/System.map-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
 255 mkinitrd /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
 256 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
 257 that comes first is the default kernel)
 258 ybin
 259 select the right entry at the yaboot prompt (see choices : tab, select : type
 260 the kernel name followed by enter)
 261 Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
 262 --
 263 </PRE>
 264
 265 <h3><a href="#TOCeditconfig" name="editconfig">Editing the system wide
 266 configuration</a></h3>
 267
 268 <p>
 269 You must activate debugfs and specify a mount point. This is typically done in
 270 fstab such that it happens at boot time.  If you have never used DebugFS before,
 271 these operation would do this for you :
 272
 273 <PRE>
 274 mkdir /mnt/debugfs
 275 cp /etc/fstab /etc/fstab.lttng.bkp
 276 echo "debugfs         /mnt/debugfs    debugfs rw              0       0"  >> /etc/fstab
 277 </PRE>
 278
 279 <p>
 280 then, rebooting or issuing the following command will activate debugfs :
 281 <PRE>
 282 mount /mnt/debugfs
 283 </PRE>
 284
 285 <p>
 286 You need to load the LTT modules to be able to control tracing from user
 287 space. This is done by issuing the following commands. Note however
 288 these commands load all LTT modules. Depending on what options you chose to
 289 compile statically, you may not need to issue all these commands.
 290
 291 <PRE>
 292 modprobe ltt-trace-control
 293 modprobe ltt-marker-control
 294 modprobe ltt-tracer
 295 modprobe ltt-serialize
 296 modprobe ltt-relay
 297 modprobe ipc-trace
 298 modprobe kernel-trace
 299 modprobe mm-trace
 300 modprobe net-trace
 301 modprobe fs-trace
 302 modprobe jbd2-trace
 303 modprobe ext4-trace
 304 modprobe syscall-trace
 305 modprobe trap-trace
 306 #if locking tracing is wanted, uncomment the following
 307 #modprobe lockdep-trace
 308 </PRE>
 309
 310 <p>
 311 If you want to have complete information about the kernel state (including all
 312 the process names), you need to load the ltt-statedump module. This is done by
 313 issuing the command :
 314
 315 <PRE>
 316 modprobe ltt-statedump
 317 </PRE>
 318 <p>
 319 You can automate at boot time loading the ltt-control module by :
 320
 321 <PRE>
 322 cp /etc/modules /etc/modules.bkp
 323 echo ltt-trace-control >> /etc/modules
 324 echo ltt-marker-control >> /etc/modules
 325 echo ltt-tracer >> /etc/modules
 326 echo ltt-serialize >> /etc/modules
 327 echo ltt-relay >> /etc/modules
 328 echo ipc-trace >> /etc/modules
 329 echo kernel-trace >> /etc/modules
 330 echo mm-trace >> /etc/modules
 331 echo net-trace >> /etc/modules
 332 echo fs-trace >> /etc/modules
 333 echo jbd2-trace >> /etc/modules
 334 echo ext4-trace >> /etc/modules
 335 echo syscall-trace >> /etc/modules
 336 echo trap-trace >> /etc/modules
 337 #if locking tracing is wanted, uncomment the following
 338 #echo lockdep-trace >> /etc/modules
 339 </PRE>
 340
 341
 342 <h3><a href="#TOCgetlttctl" name="getlttctl">Getting and installing the
 343 ltt-control package (on the traced machine)</a></h3>
 344 <p>
 345 (note : the ltt-control package contains lttd and lttctl. Although it has the
 346 same name as the ltt-control kernel module, they are *not* the same thing.)
 347
 348 <PRE>
 349 su -
 350 cd /usr/src
 351 wget http://ltt.polymtl.ca/lttng/ltt-control-0.x-xxxx2006.tar.gz
 352 gzip -cd ltt-control-0.x-xxxx2008.tar.gz | tar xvof -
 353 cd ltt-control-0.x-xxxx2006
 354 (refer to README to see the development libraries that must be installed on you
 355 system)
 356 ./configure
 357 make
 358 make install
 359 </PRE>
 360
 361 <h3><a href="#TOCuserspacetracing" name="userspacetracing">Userspace tracing</a></h3>
 362
 363 <PRE>
 364 Make sure you selected the kernel menuconfig option :
 365     <M> or <*> Support logging events from userspace
 366 And that the ltt-userspace-event kernel module is loaded if selected as a
 367 module.
 368
 369 Simple userspace tracing is available through
 370 echo "some text to record" > /mnt/debugfs/ltt/write_event
 371
 372 It will appear in the trace under event :
 373 channel : userspace
 374 event name : event
 375 </PRE>
 376
 377 <h3><a href="#TOCgetlttv" name="getlttv">Getting and installing the LTTV package
 378 (on the visualisation machine, same
 379 or different from the visualisation machine)</a></h3>
 380
 381 <PRE>
 382 su -
 383 cd /usr/src
 384 wget http://ltt.polymtl.ca/packages/lttv-0.x.xx-xxxx2008.tar.gz
 385 gzip -cd lttv-0.x.xx-xxxx2008.tar.gz | tar xvof -
 386 cd lttv-0.x.xx-xxxx2008
 387 (refer to README to see the development libraries that must be installed on your
 388 system)
 389 ./configure
 390 make
 391 make install
 392 </PRE>
 393
 394 <hr />
 395
 396
 397 <h2><a href="#TOCsection2" name="section2">Using LTTng and LTTV</a></h2>
 398
 399 <li><b>IMPORTANT : Arm Linux Kernel Markers after each boot before tracing</b></li>
 400 <PRE>
 401 ltt-armall
 402 </PRE>
 403
 404 <h3><a href="#TOCuselttvgui" name="uselttvgui">Use graphical LTTV to control
 405 tracing and analyse traces</a></h3>
 406 <PRE>
 407 lttv-gui (or /usr/local/bin/lttv-gui)
 408   - Spot the "Tracing Control" icon : click on it
 409       (it's a traffic light icon)
 410     - enter the root password
 411     - click "start"
 412     - click "stop"
 413     - Yes
 414       * You should now see a trace
 415 </PRE>
 416
 417 <h3><a href="#TOCuselttngtext" name="uselttngtext">Use text mode LTTng to control tracing</a></h3>
 418 <PRE>
 419 The tracing can be controlled from a terminal by using the lttctl command (as
 420 root).
 421
 422 Start tracing :
 423
 424 lttctl -C -w /tmp/trace1 trace1
 425
 426 Stop tracing and destroy trace channels :
 427
 428 lttctl -D trace1
 429
 430 see lttctl --help for details.
 431 </PRE>
 432 <p>
 433 (note : to see if the buffers has been filled, look at the dmesg output after
 434 lttctl -D or after stopping tracing from the GUI, it will show an event lost
 435 count. If it is the case, try using larger buffers. See lttctl --help to learn
 436 how. lttv now also shows event lost messages in the console when loading a trace
 437 with missing events or lost subbuffers.)
 438
 439 <h3><a href="#TOCuselttvtext" name="uselttvtext">Use text mode LTTV</a></h3>
 440 <p>
 441 Feel free to look in /usr/local/lib/lttv/plugins to see all the text and
 442 graphical plugins available.
 443 <p>
 444 For example, a simple trace dump in text format is available with :
 445 <PRE>
 446 lttv -m textDump -t /tmp/trace
 447 </PRE>
 448 <p>
 449 See lttv -m textDump --help for detailed command line options of textDump.
 450 <p>
 451 It is, in the current state of the project, very useful to use "grep" on the
 452 text output to filter by specific event fields. You can later copy the timestamp
 453 of the events to the clipboard and paste them in the GUI by clicking on the
 454 bottom right label "Current time". Support for this type of filtering should
 455 be added to the filter module soon.
 456
 457 <h3><a href="#TOChybrid" name="hybrid">Tracing in "Hybrid" mode</a></h3>
 458 <p>
 459 Starting from LTTng 0.5.105 and ltt-control 0.20, a new mode can be used :
 460 hybrid. It can be especially useful when studying big workloads on a long period
 461 of time.
 462 <p>
 463 When using this mode, the most important, low rate control information will be
 464 recorded during all the trace by lttd (i.e. process creation/exit). The high
 465 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
 466 flight recorder buffer (now named flight-channelname_X).
 467 <p>
 468 The following lttctl commands take an hybrid trace :
 469 <p>
 470 Create trace channel, start lttd on normal channels, start tracing:
 471 <PRE>
 472 lttctl -C -w /tmp/trace2 -o channel.kernel.overwrite=1 trace2
 473 </PRE>
 474 <p>
 475 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
 476 <PRE>
 477 lttctl -D -w /tmp/trace2 trace2
 478 </PRE>
 479 <p>
 480 Each "overwrite" channel is flight recorder channel.
 481
 482
 483 <h3><a href="#TOCflight" name="flight">Tracing in flight recorder mode</a></h3>
 484 <li>Flight recorder mode</li>
 485 <p>
 486 The flight recorder mode writes data into overwritten buffers for all channels,
 487 including control channels, except for the facilities tracefiles. It consists of
 488 setting all channels to "overwrite".
 489 <p>
 490 The following lttctl commands take a flight recorder trace :
 491 <PRE>
 492 lttctl -C -w /tmp/trace3 -o channel.all.overwrite=1 trace3
 493 ...
 494 lttctl -D -w /tmp/trace3 trace3
 495 </PRE>
 496
 497 <hr />
 498
 499
 500 <h2><a href="#TOCsection3" name="section3">Adding new instrumentations with the
 501 markers</a></h2>
 502 <p>
 503
 504 <h3><a href="#TOCkerneltp" name="kerneltp">Adding kernel
 505 instrumentation</a></h3>
 506
 507 <p>
 508 See <a
 509 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>
 510 and <a
 511 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
 512 tree.
 513 <p>
 514 Also see <a
 515 href="http://git.kernel.org/?p=linux/kernel/git/compudj/linux-2.6-lttng.git;a=tree;f=ltt/probes">ltt/probes/</a>
 516 for LTTng probe examples.
 517
 518 <h3><a href="#TOCusertp" name="usertp">Adding userspace instrumentation</a></h3>
 519
 520 Add new events to userspace programs with
 521 <a href="http://ltt.polymtl.ca/packages/">userspace markers packages</a>.
 522 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
 523 allows inserting markers in executables and libraries, currently only on x86_32
 524 and x86_64.
 525 See <a
 526 href="http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2">markers-userspace-0.5.tar.bz2</a> or more recent.
 527
 528 <p>
 529 Note that a new design document for a 3rd generation of tracepoint/marker-based
 530 userspace tracing is available at <a
 531 href="http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/ust.html">LTTng User-space Tracing
 532 Design</a>. This new infrastructure is not yet implemented.
 533
 534 <p>
 535 The easy quick-and-dirty way to perform userspace tracing is currently to write
 536 an string to /mnt/debugfs/ltt/write_event. See <a
 537 href="#userspacetracing">Userspace tracing</a> in the
 538 installation for sources section of this document.
 539
 540 <hr />
 541
 542 <h2><a href="#TOCsection4" name="section4">Creating Debian or RPM packages</a></h2>
 543 <p>
 544
 545 <h3><a href="#TOCpkgdebian" name="pkgdebian">Create custom LTTV Debian packages</a></h3>
 546
 547 <PRE>
 548 Use : dpkg-buildpackage -rfakeroot
 549 </PRE>
 550 <p>
 551 You should then have your LTTV .deb files created for your architecture.
 552
 553 <h3><a href="#TOCpkglttng" name="pkglttng">Create custom LTTng packages</a></h3>
 554 <p>
 555 For building LTTng Debian packages :
 556 get the build tree with patches applies as explained in section 2.
 557
 558 <PRE>
 559 make menuconfig (or xconfig or config) (customize your configuration)
 560 make-kpkg kernel_image
 561 </PRE>
 562 <p>
 563 You will then see your freshly created .deb in /usr/src. Install it with
 564 <PRE>
 565 dpkg -i /usr/src/(image-name).deb
 566 </PRE>
 567 <p>
 568 Then, follow the section "Editing the system wide configuration" in section 2.
 569
 570 <hr />
 571
 572   </body>
 573 </html>