trunk/lttv/QUICKSTART.html

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   4   <title>Linux Trace Toolkit Next Generation User Documentation</title>
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   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 <ul>
  16
  17 <li><a href="#intro" name="TOCintro">Introduction</a></li>
  18 <li><a href="#section1" name="TOCsection1">Installing LTTng and LTTV from
  19 sources</a></li>
  20 <li><a href="#section2" name="TOCsection2">Using LTTng and LTTV</a></li>
  21 <li><a href="#section3" name="TOCsection3">Adding kernel and user-space
  22 tracepoints</a></li>
  23 <li><a href="#section4" name="TOCsection4">Creating Debian and RPM packages
  24 from LTTV</a>
  25
  26 </ul>
  27
  28 <hr />
  29
  30 <h2><a href="#TOCintro" name="intro">Introduction</a></h2>
  31 <p>
  32 This document is made of four parts : the first one explains how
  33 to install LTTng and LTTV from sources, the second one describes the steps
  34 to follow to trace a system and view it. The third part explains
  35 briefly how to add a new trace point to the kernel and to user space
  36 applications. The fourth and last part explains how to create Debian or RPM
  37 packages from the LTTng and LTTV sources.
  38 <p>
  39 These operations are made for installing the LTTng 0.86 tracer on a linux 2.6.X
  40 kernel. You will also find instructions for installation of LTTV 0.12.x : the
  41 Linux Trace Toolkit Viewer.
  42 To see the list of compatibilities between LTTng, ltt-control, LTTV, please
  43 refer to :
  44 <a
  45 href="http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV versions compatibility</a>
  46 The lttng patch is necessary to have the tracing hooks in the kernel.
  47
  48 <br>
  49 <br>
  50 Supported architectures :
  51 <br>
  52 LTTng :<br>
  53 <li> x86 32/64 bits
  54 <li> PowerPC 32 and 64 bits
  55 <li> ARM (with limited timestamping precision, e.g. 1HZ. Need
  56 architecture-specific support for better precision)
  57 <li> MIPS
  58 <br>
  59 <br>
  60 LTTV :<br>
  61 <li> Intel 32/64 bits
  62 <li> PowerPC 32 and 64 bits
  63 <li> Possibly others. Takes care of endianness and type size difference between
  64 the LTTng traces and the LTTV analysis tool.
  65
  66 <hr />
  67
  68
  69 <h2><a href="#TOCsection1" name="section1">Installation from sources</a></h2>
  70 <p>
  71
  72 <li>Prerequisites</li>
  73 <ul>
  74 <p>
  75 Tools needed to follow the package download steps :
  76
  77 <li>wget
  78 <li>bzip2
  79 <li>gzip
  80 <li>tar
  81
  82 <p>
  83 You have to install the standard development libraries and programs necessary
  84 to compile a kernel :
  85
  86 <PRE>
  87 (from Documentation/Changes in the Linux kernel tree)
  88 Gnu C                2.95.3                # gcc --version
  89 Gnu make             3.79.1                # make --version
  90 binutils             2.12                  # ld -v
  91 util-linux           2.10o                 # fdformat --version
  92 module-init-tools    0.9.10                # depmod -V
  93 </PRE>
  94
  95 <p>
  96 You might also want to have libncurses5 to have the text mode kernel
  97 configuration menu, but there are alternatives.
  98
  99 <p>
 100 Prerequisites for LTTV 0.x.x installation are :
 101
 102 <PRE>
 103 gcc 3.2 or better
 104 gtk 2.4 or better development libraries
 105   (Debian : libgtk2.0, libgtk2.0-dev)
 106   (Fedora : gtk2, gtk2-devel)
 107   note : For Fedora users : this might require at least core 3 from Fedora,
 108   or you might have to compile your own GTK2 library.
 109 glib 2.4 or better development libraries
 110   (Debian : libglib2.0-0, libglib2.0-dev)
 111   (Fedora : glib2, glib2-devel)
 112 libpopt development libraries
 113   (Debian : libpopt0, libpopt-dev)
 114   (Fedora : popt)
 115 libpango development libraries
 116   (Debian : libpango1.0, libpango1.0-dev)
 117   (Fedora : pango, pango-devel)
 118 libc6 development librairies
 119   (Debian : libc6, libc6-dev)
 120   (Fedora : glibc, glibc)
 121 </PRE>
 122 </ul>
 123
 124 <li>Reminder</li>
 125
 126 <p>
 127 See the list of compatibilities between LTTng, ltt-control and LTTV at :
 128 <a
 129 href="http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV
 130 versions compatibility</a>.
 131
 132
 133 <li>Getting the LTTng packages</li>
 134
 135 <PRE>
 136 su -
 137 mkdir /usr/src/lttng
 138 cd /usr/src/lttng
 139 (see http://ltt.polymtl.ca/lttng for package listing)
 140 wget http://ltt.polymtl.ca/lttng/patch-2.6.X-lttng-0.x.xx.tar.bz2
 141 bzip2 -cd patch-2.6.X-lttng-0.x.xx.tar.bz2 | tar xvof -
 142 </PRE>
 143
 144
 145 <li>Getting LTTng kernel sources</li>
 146
 147 <PRE>
 148 su -
 149 cd /usr/src
 150 wget http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.X.tar.bz2
 151 bzip2 -cd linux-2.6.X.tar.bz2 | tar xvof -
 152 cd linux-2.6.X
 153 - For LTTng 0.9.4- cat /usr/src/lttng/patch*-2.6.X-lttng-0.x.xx* | patch -p1
 154 - For LTTng 0.9.5+ apply the patches in the order specified in the series file,
 155   or use quilt
 156 cd ..
 157 mv linux-2.6.X linux-2.6.X-lttng-0.x.xx
 158 </PRE>
 159
 160
 161 <li>Installing a LTTng kernel</li>
 162
 163 <PRE>
 164 su -
 165 cd /usr/src/linux-2.6.X-lttng-0.x.xx
 166 make menuconfig (or make xconfig or make config)
 167     Select the < Help > button if you are not familiar with kernel
 168     configuration.
 169     Items preceded by [*] means they has to be built into the kernel.
 170     Items preceded by [M] means they has to be built as modules.
 171     Items preceded by [ ] means they should be removed.
 172   go to the "General setup" section
 173     Select the following options :
 174     [*] Prompt for development and/or incomplete code/drivers
 175     [*] Activate markers
 176     [*] Activate userspace markers ABI (experimental, optional)
 177     [*] Immediate value optimization (optional)
 178     [*] Linux Trace Toolkit Next Generation (LTTng) --->
 179     <M> or <*> Compile lttng tracing probes
 180     <M> or <*> Linux Trace Toolkit High-speed Lockless Data Relay
 181     <M> or <*> Linux Trace Toolkit Lock-Protected Data Relay
 182     <M> or <*> Linux Trace Toolkit Serializer
 183     <M> or <*>   Linux Trace Toolkit Marker Control
 184     <M> or <*>     Linux Trace Toolkit Tracer
 185     [*] Align Linux Trace Toolkit Traces
 186     <M> or <*> Support logging events from userspace
 187     [*] Support trace extraction from crash dump
 188     <M> or <*> Linux Trace Toolkit Trace Controller
 189     <M> or <*> Linux Trace Toolkit State Dump
 190   Select <Exit>
 191   Select <Exit>
 192   Select <Yes>
 193 make
 194 make modules_install
 195 (if necessary, create a initrd with mkinitrd or your preferate alternative)
 196 (mkinitrd -o /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx)
 197
 198 -- on X86, X86_64
 199 make install
 200 reboot
 201 Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
 202
 203 -- on PowerPC
 204 cp vmlinux.strip /boot/vmlinux-2.6.X-lttng-0.x.xx
 205 cp System.map /boot/System.map-2.6.X-lttng-0.x.xx
 206 cp .config /boot/config-2.6.X-lttng-0.x.xx
 207 depmod -ae -F /boot/System.map-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
 208 mkinitrd /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
 209 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
 210 that comes first is the default kernel)
 211 ybin
 212 select the right entry at the yaboot prompt (see choices : tab, select : type
 213 the kernel name followed by enter)
 214 Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
 215 --
 216 </PRE>
 217
 218 <li>Editing the system wide configuration</li>
 219
 220 <p>
 221 You must activate debugfs and specify a mount point. This is typically done in
 222 fstab such that it happens at boot time.  If you have never used DebugFS before,
 223 these operation would do this for you :
 224
 225 <PRE>
 226 mkdir /mnt/debugfs
 227 cp /etc/fstab /etc/fstab.lttng.bkp
 228 echo "debugfs         /mnt/debugfs    debugfs rw              0       0"  >> /etc/fstab
 229 </PRE>
 230
 231 <p>
 232 then, rebooting or issuing the following command will activate debugfs :
 233 <PRE>
 234 mount /mnt/debugfs
 235 </PRE>
 236
 237 <p>
 238 You need to load the LTT modules to be able to control tracing from user
 239 space. This is done by issuing the following commands. Note however
 240 these commands load all LTT modules. Depending on what options you chose to
 241 compile statically, you may not need to issue all these commands.
 242
 243 <PRE>
 244 modprobe ltt-trace-control
 245 modprobe ltt-marker-control
 246 modprobe ltt-tracer
 247 modprobe ltt-serialize
 248 modprobe ltt-relay
 249 modprobe ipc-trace
 250 modprobe kernel-trace
 251 modprobe mm-trace
 252 modprobe net-trace
 253 modprobe fs-trace
 254 modprobe jbd2-trace
 255 modprobe ext4-trace
 256 modprobe syscall-trace
 257 modprobe trap-trace
 258 #if locking tracing is wanted, uncomment the following
 259 #modprobe lockdep-trace
 260 </PRE>
 261
 262 <p>
 263 If you want to have complete information about the kernel state (including all
 264 the process names), you need to load the ltt-statedump module. This is done by
 265 issuing the command :
 266
 267 <PRE>
 268 modprobe ltt-statedump
 269 </PRE>
 270 <p>
 271 You can automate at boot time loading the ltt-control module by :
 272
 273 <PRE>
 274 cp /etc/modules /etc/modules.bkp
 275 echo ltt-trace-control >> /etc/modules
 276 echo ltt-marker-control >> /etc/modules
 277 echo ltt-tracer >> /etc/modules
 278 echo ltt-serialize >> /etc/modules
 279 echo ltt-relay >> /etc/modules
 280 echo ipc-trace >> /etc/modules
 281 echo kernel-trace >> /etc/modules
 282 echo mm-trace >> /etc/modules
 283 echo net-trace >> /etc/modules
 284 echo fs-trace >> /etc/modules
 285 echo jbd2-trace >> /etc/modules
 286 echo ext4-trace >> /etc/modules
 287 echo syscall-trace >> /etc/modules
 288 echo trap-trace >> /etc/modules
 289 #if locking tracing is wanted, uncomment the following
 290 #echo lockdep-trace >> /etc/modules
 291 </PRE>
 292
 293 <li>Getting and installing the ltt-control package (on the traced machine)</li>
 294 <p>
 295 (note : the ltt-control package contains lttd and lttctl. Although it has the
 296 same name as the ltt-control kernel module, they are *not* the same thing.)
 297
 298 <PRE>
 299 su -
 300 cd /usr/src
 301 wget http://ltt.polymtl.ca/lttng/ltt-control-0.x-xxxx2006.tar.gz
 302 gzip -cd ltt-control-0.x-xxxx2008.tar.gz | tar xvof -
 303 cd ltt-control-0.x-xxxx2006
 304 (refer to README to see the development libraries that must be installed on you
 305 system)
 306 ./configure
 307 make
 308 make install
 309 </PRE>
 310
 311 <li>Userspace tracing</li>
 312
 313 <PRE>
 314 Make sure you selected the kernel menuconfig option :
 315     <M> or <*> Support logging events from userspace
 316 And that the ltt-userspace-event kernel module is loaded if selected as a
 317 module.
 318
 319 Simple userspace tracing is available through
 320 echo "some text to record" > /mnt/debugfs/ltt/write_event
 321
 322 It will appear in the trace under event :
 323 channel : userspace
 324 event name : event
 325 </PRE>
 326
 327 <li>Getting and installing the LTTV package (on the visualisation machine, same
 328 or different from the visualisation machine)</li>
 329
 330 <PRE>
 331 su -
 332 cd /usr/src
 333 wget http://ltt.polymtl.ca/packages/lttv-0.x.xx-xxxx2008.tar.gz
 334 gzip -cd lttv-0.x.xx-xxxx2008.tar.gz | tar xvof -
 335 cd lttv-0.x.xx-xxxx2008
 336 (refer to README to see the development libraries that must be installed on your
 337 system)
 338 ./configure
 339 make
 340 make install
 341 </PRE>
 342
 343 <hr />
 344
 345
 346 <h2><a href="#TOCsection2" name="section2">Using LTTng and LTTV</a></h2>
 347
 348 <li>IMPORTANT : Arm Linux Kernel Markers after each boot</li>
 349 <PRE>
 350 ltt-armall
 351 </PRE>
 352
 353 <li>Use graphical LTTV to control tracing and analyse traces</li>
 354 <PRE>
 355 lttv-gui (or /usr/local/bin/lttv-gui)
 356   - Spot the "Tracing Control" icon : click on it
 357       (it's a traffic light icon)
 358     - enter the root password
 359     - click "start"
 360     - click "stop"
 361     - Yes
 362       * You should now see a trace
 363 </PRE>
 364
 365 <li>Use text mode LTTng to control tracing</li>
 366 <PRE>
 367 The tracing can be controlled from a terminal by using the lttctl command (as
 368 root).
 369
 370 Start tracing :
 371
 372 lttctl -C -w /tmp/trace1 trace1
 373
 374 Stop tracing and destroy trace channels :
 375
 376 lttctl -D trace1
 377
 378 see lttctl --help for details.
 379 </PRE>
 380 <p>
 381 (note : to see if the buffers has been filled, look at the dmesg output after
 382 lttctl -R or after stopping tracing from the GUI, it will show an event lost
 383 count. If it is the case, try using larger buffers. See lttctl --help to learn
 384 how. lttv now also shows event lost messages in the console when loading a trace
 385 with missing events or lost subbuffers.)
 386
 387 <li>Use text mode LTTV</li>
 388 <p>
 389 Feel free to look in /usr/local/lib/lttv/plugins to see all the text and
 390 graphical plugins available.
 391 <p>
 392 For example, a simple trace dump in text format is available with :
 393 <PRE>
 394 lttv -m textDump -t /tmp/trace
 395 </PRE>
 396 <p>
 397 See lttv -m textDump --help for detailed command line options of textDump.
 398 <p>
 399 It is, in the current state of the project, very useful to use "grep" on the
 400 text output to filter by specific event fields. You can later copy the timestamp
 401 of the events to the clipboard and paste them in the GUI by clicking on the
 402 bottom right label "Current time". Support for this type of filtering should
 403 be added to the filter module soon.
 404
 405 <li>Hybrid mode</li>
 406 <p>
 407 Starting from LTTng 0.5.105 and ltt-control 0.20, a new mode can be used :
 408 hybrid. It can be especially useful when studying big workloads on a long period
 409 of time.
 410 <p>
 411 When using this mode, the most important, low rate control information will be
 412 recorded during all the trace by lttd (i.e. process creation/exit). The high
 413 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
 414 flight recorder buffer (now named flight-channelname_X).
 415 <p>
 416 The following lttctl commands take an hybrid trace :
 417 <p>
 418 Create trace channel, start lttd on normal channels, start tracing:
 419 <PRE>
 420 lttctl -C -w /tmp/trace2 -o channel.kernel.overwrite=1 trace2
 421 </PRE>
 422 <p>
 423 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
 424 <PRE>
 425 lttctl -D -w /tmp/trace2 trace2
 426 </PRE>
 427 <p>
 428 Each "overwrite" channel is flight recorder channel.
 429
 430 <li>Flight recorder mode</li>
 431 <p>
 432 The flight recorder mode writes data into overwritten buffers for all channels,
 433 including control channels, except for the facilities tracefiles. It consists of
 434 setting all channels to "overwrite".
 435 <p>
 436 The following lttctl commands take a flight recorder trace :
 437 <PRE>
 438 lttctl -C -w /tmp/trace3 -o channel.all.overwrite=1 trace3
 439 ...
 440 lttctl -D -w /tmp/trace3 trace3
 441 </PRE>
 442
 443 <hr />
 444
 445
 446 <h2><a href="#TOCsection3" name="section3">Adding new instrumentations with the
 447 markers</a></h2>
 448 <p>
 449
 450 <p>
 451 See Documentation/markers.txt and Documentation/tracepoints.txt in your kernel
 452 tree.
 453
 454 <li>Add new events to userspace programs with
 455 <a href="http://ltt.polymtl.ca/packages/">userspace markers packages</a></li>
 456
 457 <p>
 458 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
 459 allows inserting markers in executables and libraries, currently only on x86_32
 460 and x86_64.
 461
 462 See <a
 463 href="http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2">markers-userspace-0.5.tar.bz2</a> or more recent.
 464
 465 Note that a new design document for a 3rd generation of tracepoint/marker-based
 466 userspace tracing is available at <a
 467 href="http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/ust.html">LTTng User-space Tracing
 468 Design"</a>.
 469
 470 <hr />
 471
 472 <h2><a href="#TOCsection4" name="section4">Creating Debian or RPM packages</a></h2>
 473 <p>
 474
 475 <li>Create custom LTTV Debian packages</li>
 476
 477 <PRE>
 478 Use : dpkg-buildpackage -rfakeroot
 479 </PRE>
 480 <p>
 481 You should then have your LTTV .deb files created for your architecture.
 482
 483 <li>Create custom LTTng packages</li>
 484 <p>
 485 For building LTTng Debian packages :
 486 get the build tree with patches applies as explained in section 2.
 487
 488 <PRE>
 489 make menuconfig (or xconfig or config) (customize your configuration)
 490 make-kpkg kernel_image
 491 </PRE>
 492 <p>
 493 You will then see your freshly created .deb in /usr/src. Install it with
 494 <PRE>
 495 dpkg -i /usr/src/(image-name).deb
 496 </PRE>
 497 <p>
 498 Then, follow the section "Editing the system wide configuration" in section 2.
 499
 500
 501
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