LTTngManual.html

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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> ARMv7 OMAP3
  97 <li> Other ARM (with limited timestamping precision, e.g. 1HZ. Need
  98 architecture-specific support for better precision)
  99 <li> MIPS
 100 <li> sh (partial architecture-specific instrumentation)
 101 <li> sparc64 (partial architecture-specific instrumentation)
 102 <li> s390 (partial architecture-specific instrumentation)
 103 <li> Other architectures supported without architecture-specific instrumentation
 104 and with low-resolution timestamps.<br>
 105 <br>
 106 <br>
 107 LTTV :<br>
 108 <br>
 109 <li> Intel 32/64 bits
 110 <li> PowerPC 32 and 64 bits
 111 <li> Possibly others. Takes care of endianness and type size difference between
 112 the LTTng traces and the LTTV analysis tool.
 113
 114 <hr />
 115
 116
 117 <h2><a href="#TOCsection1" name="section1">Installation from sources</a></h2>
 118 <p>
 119
 120 <h3><a href="#TOCprerequisites" name="prerequisites">Prerequisites</a></h3>
 121 <ul>
 122 <p>
 123 Tools needed to follow the package download steps :
 124
 125 <li>wget
 126 <li>bzip2
 127 <li>gzip
 128 <li>tar
 129
 130 <p>
 131 You have to install the standard development libraries and programs necessary
 132 to compile a kernel :
 133
 134 <PRE>
 135 (from Documentation/Changes in the Linux kernel tree)
 136 Gnu C                2.95.3                # gcc --version
 137 Gnu make             3.79.1                # make --version
 138 binutils             2.12                  # ld -v
 139 util-linux           2.10o                 # fdformat --version
 140 module-init-tools    0.9.10                # depmod -V
 141 </PRE>
 142
 143 <p>
 144 You might also want to have libncurses5 to have the text mode kernel
 145 configuration menu, but there are alternatives.
 146
 147 <p>
 148 Prerequisites for LTTV 0.x.x installation are :
 149
 150 <PRE>
 151 gcc 3.2 or better
 152 gtk 2.4 or better development libraries
 153   (Debian : libgtk2.0, libgtk2.0-dev)
 154   (Fedora : gtk2, gtk2-devel)
 155   note : For Fedora users : this might require at least core 3 from Fedora,
 156   or you might have to compile your own GTK2 library.
 157 glib 2.4 or better development libraries
 158   (Debian : libglib2.0-0, libglib2.0-dev)
 159   (Fedora : glib2, glib2-devel)
 160 libpopt development libraries
 161   (Debian : libpopt0, libpopt-dev)
 162   (Fedora : popt)
 163 libpango development libraries
 164   (Debian : libpango1.0, libpango1.0-dev)
 165   (Fedora : pango, pango-devel)
 166 libc6 development librairies
 167   (Debian : libc6, libc6-dev)
 168   (Fedora : glibc, glibc)
 169 </PRE>
 170 </ul>
 171
 172 <li>Reminder</li>
 173
 174 <p>
 175 See the list of compatibilities between LTTng, ltt-control and LTTV at :
 176 <a
 177 href="http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/lttng-lttv-compatibility.html">LTTng+LTTV
 178 versions compatibility</a>.
 179
 180
 181 <h3><a href="#TOCgetlttng" name="getlttng">Getting the LTTng packages</a></h3>
 182
 183 <PRE>
 184 su -
 185 mkdir /usr/src/lttng
 186 cd /usr/src/lttng
 187 (see http://ltt.polymtl.ca/lttng for package listing)
 188 wget http://ltt.polymtl.ca/lttng/patch-2.6.X-lttng-0.x.xx.tar.bz2
 189 bzip2 -cd patch-2.6.X-lttng-0.x.xx.tar.bz2 | tar xvof -
 190 </PRE>
 191
 192
 193 <h3><a href="#TOCgetlttngsrc" name="getlttngsrc">Getting LTTng kernel sources</a></h3>
 194
 195 <PRE>
 196 su -
 197 cd /usr/src
 198 wget http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.X.tar.bz2
 199 bzip2 -cd linux-2.6.X.tar.bz2 | tar xvof -
 200 cd linux-2.6.X
 201 - For LTTng 0.9.4- cat /usr/src/lttng/patch*-2.6.X-lttng-0.x.xx* | patch -p1
 202 - For LTTng 0.9.5+ apply the patches in the order specified in the series file,
 203   or use quilt
 204 cd ..
 205 mv linux-2.6.X linux-2.6.X-lttng-0.x.xx
 206 </PRE>
 207
 208
 209 <h3><a href="#TOCinstalllttng" name="installlttng">Installing a LTTng kernel</a></h3>
 210
 211 <PRE>
 212 su -
 213 cd /usr/src/linux-2.6.X-lttng-0.x.xx
 214 make menuconfig (or make xconfig or make config)
 215     Select the < Help > button if you are not familiar with kernel
 216     configuration.
 217     Items preceded by [*] means they has to be built into the kernel.
 218     Items preceded by [M] means they has to be built as modules.
 219     Items preceded by [ ] means they should be removed.
 220   go to the "General setup" section
 221     Select the following options :
 222     [*] Prompt for development and/or incomplete code/drivers
 223     [*] Activate markers
 224     [*] Activate userspace markers ABI (experimental, optional)
 225     [*] Immediate value optimization (optional)
 226     [*] Linux Trace Toolkit Next Generation (LTTng) --->
 227     <M> or <*> Compile lttng tracing probes
 228     <M> or <*> Linux Trace Toolkit High-speed Lockless Data Relay
 229     <M> or <*> Linux Trace Toolkit Lock-Protected Data Relay
 230     <M> or <*> Linux Trace Toolkit Serializer
 231     <M> or <*>   Linux Trace Toolkit Marker Control
 232     <M> or <*>     Linux Trace Toolkit Tracer
 233     [*] Align Linux Trace Toolkit Traces
 234     <M> or <*> Support logging events from userspace
 235     [*] Support trace extraction from crash dump
 236     <M> or <*> Linux Trace Toolkit Trace Controller
 237     <M> or <*> Linux Trace Toolkit State Dump
 238   Select <Exit>
 239   Select <Exit>
 240   Select <Yes>
 241 make
 242 make modules_install
 243 (if necessary, create a initrd with mkinitrd or your preferate alternative)
 244 (mkinitrd -o /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx)
 245
 246 -- on X86, X86_64
 247 make install
 248 reboot
 249 Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
 250
 251 -- on PowerPC
 252 cp vmlinux.strip /boot/vmlinux-2.6.X-lttng-0.x.xx
 253 cp System.map /boot/System.map-2.6.X-lttng-0.x.xx
 254 cp .config /boot/config-2.6.X-lttng-0.x.xx
 255 depmod -ae -F /boot/System.map-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
 256 mkinitrd /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
 257 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
 258 that comes first is the default kernel)
 259 ybin
 260 select the right entry at the yaboot prompt (see choices : tab, select : type
 261 the kernel name followed by enter)
 262 Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
 263 --
 264 </PRE>
 265
 266 <h3><a href="#TOCeditconfig" name="editconfig">Editing the system wide
 267 configuration</a></h3>
 268
 269 <p>
 270 You must activate debugfs and specify a mount point. This is typically done in
 271 fstab such that it happens at boot time.  If you have never used DebugFS before,
 272 these operation would do this for you :
 273
 274 <PRE>
 275 mkdir /mnt/debugfs
 276 cp /etc/fstab /etc/fstab.lttng.bkp
 277 echo "debugfs         /mnt/debugfs    debugfs rw              0       0"  >> /etc/fstab
 278 </PRE>
 279
 280 <p>
 281 then, rebooting or issuing the following command will activate debugfs :
 282 <PRE>
 283 mount /mnt/debugfs
 284 </PRE>
 285
 286 <p>
 287 You need to load the LTT modules to be able to control tracing from user
 288 space. This is done by issuing the following commands. Note however
 289 these commands load all LTT modules. Depending on what options you chose to
 290 compile statically, you may not need to issue all these commands.
 291
 292 <PRE>
 293 modprobe ltt-trace-control
 294 modprobe ltt-marker-control
 295 modprobe ltt-tracer
 296 modprobe ltt-serialize
 297 modprobe ltt-relay
 298 modprobe ipc-trace
 299 modprobe kernel-trace
 300 modprobe mm-trace
 301 modprobe net-trace
 302 modprobe fs-trace
 303 modprobe jbd2-trace
 304 modprobe ext4-trace
 305 modprobe syscall-trace
 306 modprobe trap-trace
 307 #if locking tracing is wanted, uncomment the following
 308 #modprobe lockdep-trace
 309 </PRE>
 310
 311 <p>
 312 If you want to have complete information about the kernel state (including all
 313 the process names), you need to load the ltt-statedump module. This is done by
 314 issuing the command :
 315
 316 <PRE>
 317 modprobe ltt-statedump
 318 </PRE>
 319 <p>
 320 You can automate at boot time loading the ltt-control module by :
 321
 322 <PRE>
 323 cp /etc/modules /etc/modules.bkp
 324 echo ltt-trace-control >> /etc/modules
 325 echo ltt-marker-control >> /etc/modules
 326 echo ltt-tracer >> /etc/modules
 327 echo ltt-serialize >> /etc/modules
 328 echo ltt-relay >> /etc/modules
 329 echo ipc-trace >> /etc/modules
 330 echo kernel-trace >> /etc/modules
 331 echo mm-trace >> /etc/modules
 332 echo net-trace >> /etc/modules
 333 echo fs-trace >> /etc/modules
 334 echo jbd2-trace >> /etc/modules
 335 echo ext4-trace >> /etc/modules
 336 echo syscall-trace >> /etc/modules
 337 echo trap-trace >> /etc/modules
 338 #if locking tracing is wanted, uncomment the following
 339 #echo lockdep-trace >> /etc/modules
 340 </PRE>
 341
 342
 343 <h3><a href="#TOCgetlttctl" name="getlttctl">Getting and installing the
 344 ltt-control package (on the traced machine)</a></h3>
 345 <p>
 346 (note : the ltt-control package contains lttd and lttctl. Although it has the
 347 same name as the ltt-control kernel module, they are *not* the same thing.)
 348
 349 <PRE>
 350 su -
 351 cd /usr/src
 352 wget http://ltt.polymtl.ca/lttng/ltt-control-0.x-xxxx2006.tar.gz
 353 gzip -cd ltt-control-0.x-xxxx2008.tar.gz | tar xvof -
 354 cd ltt-control-0.x-xxxx2006
 355 (refer to README to see the development libraries that must be installed on you
 356 system)
 357 ./configure
 358 make
 359 make install
 360 # (run ldconfig to ensure new shared objects are taken into account)
 361 ldconfig
 362 </PRE>
 363
 364 <h3><a href="#TOCuserspacetracing" name="userspacetracing">Userspace tracing</a></h3>
 365
 366 <PRE>
 367 Make sure you selected the kernel menuconfig option :
 368     <M> or <*> Support logging events from userspace
 369 And that the ltt-userspace-event kernel module is loaded if selected as a
 370 module.
 371
 372 Simple userspace tracing is available through
 373 echo "some text to record" > /mnt/debugfs/ltt/write_event
 374
 375 It will appear in the trace under event :
 376 channel : userspace
 377 event name : event
 378 </PRE>
 379
 380 <h3><a href="#TOCgetlttv" name="getlttv">Getting and installing the LTTV package
 381 (on the visualisation machine, same
 382 or different from the visualisation machine)</a></h3>
 383
 384 <PRE>
 385 su -
 386 cd /usr/src
 387 wget http://ltt.polymtl.ca/packages/lttv-0.x.xx-xxxx2008.tar.gz
 388 gzip -cd lttv-0.x.xx-xxxx2008.tar.gz | tar xvof -
 389 cd lttv-0.x.xx-xxxx2008
 390 (refer to README to see the development libraries that must be installed on your
 391 system)
 392 ./configure
 393 make
 394 make install
 395 # (run ldconfig to ensure new shared objects are taken into account)
 396 ldconfig
 397 </PRE>
 398
 399 <hr />
 400
 401
 402 <h2><a href="#TOCsection2" name="section2">Using LTTng and LTTV</a></h2>
 403
 404 <li><b>IMPORTANT : Arm Linux Kernel Markers after each boot before tracing</b></li>
 405 <PRE>
 406 ltt-armall
 407 </PRE>
 408
 409 <h3><a href="#TOCuselttvgui" name="uselttvgui">Use graphical LTTV to control
 410 tracing and analyse traces</a></h3>
 411 <PRE>
 412 lttv-gui (or /usr/local/bin/lttv-gui)
 413   - Spot the "Tracing Control" icon : click on it
 414       (it's a traffic light icon)
 415     - enter the root password
 416     - click "start"
 417     - click "stop"
 418     - Yes
 419       * You should now see a trace
 420 </PRE>
 421
 422 <h3><a href="#TOCuselttngtext" name="uselttngtext">Use text mode LTTng to control tracing</a></h3>
 423 <PRE>
 424 The tracing can be controlled from a terminal by using the lttctl command (as
 425 root).
 426
 427 Start tracing :
 428
 429 lttctl -C -w /tmp/trace1 trace1
 430
 431 Stop tracing and destroy trace channels :
 432
 433 lttctl -D trace1
 434
 435 see lttctl --help for details.
 436 </PRE>
 437 <p>
 438 (note : to see if the buffers has been filled, look at the dmesg output after
 439 lttctl -D or after stopping tracing from the GUI, it will show an event lost
 440 count. If it is the case, try using larger buffers. See lttctl --help to learn
 441 how. lttv now also shows event lost messages in the console when loading a trace
 442 with missing events or lost subbuffers.)
 443
 444 <h3><a href="#TOCuselttvtext" name="uselttvtext">Use text mode LTTV</a></h3>
 445 <p>
 446 Feel free to look in /usr/local/lib/lttv/plugins to see all the text and
 447 graphical plugins available.
 448 <p>
 449 For example, a simple trace dump in text format is available with :
 450 <PRE>
 451 lttv -m textDump -t /tmp/trace
 452 </PRE>
 453 <p>
 454 See lttv -m textDump --help for detailed command line options of textDump.
 455 <p>
 456 It is, in the current state of the project, very useful to use "grep" on the
 457 text output to filter by specific event fields. You can later copy the timestamp
 458 of the events to the clipboard and paste them in the GUI by clicking on the
 459 bottom right label "Current time". Support for this type of filtering should
 460 be added to the filter module soon.
 461
 462 <h3><a href="#TOChybrid" name="hybrid">Tracing in "Hybrid" mode</a></h3>
 463 <p>
 464 Starting from LTTng 0.5.105 and ltt-control 0.20, a new mode can be used :
 465 hybrid. It can be especially useful when studying big workloads on a long period
 466 of time.
 467 <p>
 468 When using this mode, the most important, low rate control information will be
 469 recorded during all the trace by lttd (i.e. process creation/exit). The high
 470 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
 471 flight recorder buffer (now named flight-channelname_X).
 472 <p>
 473 The following lttctl commands take an hybrid trace :
 474 <p>
 475 Create trace channel, start lttd on normal channels, start tracing:
 476 <PRE>
 477 lttctl -C -w /tmp/trace2 -o channel.kernel.overwrite=1 trace2
 478 </PRE>
 479 <p>
 480 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
 481 <PRE>
 482 lttctl -D -w /tmp/trace2 trace2
 483 </PRE>
 484 <p>
 485 Each "overwrite" channel is flight recorder channel.
 486
 487
 488 <h3><a href="#TOCflight" name="flight">Tracing in flight recorder mode</a></h3>
 489 <li>Flight recorder mode</li>
 490 <p>
 491 The flight recorder mode writes data into overwritten buffers for all channels,
 492 including control channels, except for the facilities tracefiles. It consists of
 493 setting all channels to "overwrite".
 494 <p>
 495 The following lttctl commands take a flight recorder trace :
 496 <PRE>
 497 lttctl -C -w /tmp/trace3 -o channel.all.overwrite=1 trace3
 498 ...
 499 lttctl -D -w /tmp/trace3 trace3
 500 </PRE>
 501
 502 <hr />
 503
 504
 505 <h2><a href="#TOCsection3" name="section3">Adding new instrumentations with the
 506 markers</a></h2>
 507 <p>
 508
 509 <h3><a href="#TOCkerneltp" name="kerneltp">Adding kernel
 510 instrumentation</a></h3>
 511
 512 <p>
 513 See <a
 514 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>
 515 and <a
 516 href="http://git.kernel.org/?p=linux/kernel/git/compudj/linux-2.6-lttng.git;a=blob;f=Documentation/trace/tracepoints.txt">Documentation/trace/tracepoints.txt</a> in your kernel
 517 tree.
 518 <p>
 519 Also see <a
 520 href="http://git.kernel.org/?p=linux/kernel/git/compudj/linux-2.6-lttng.git;a=tree;f=ltt/probes">ltt/probes/</a>
 521 for LTTng probe examples.
 522
 523 <h3><a href="#TOCusertp" name="usertp">Adding userspace instrumentation</a></h3>
 524
 525 Add new events to userspace programs with
 526 <a href="http://ltt.polymtl.ca/packages/">userspace markers packages</a>.
 527 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
 528 allows inserting markers in executables and libraries, currently only on x86_32
 529 and x86_64.
 530 See <a
 531 href="http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2">markers-userspace-0.5.tar.bz2</a> or more recent.
 532
 533 <p>
 534 Note that a new design document for a 3rd generation of tracepoint/marker-based
 535 userspace tracing is available at <a
 536 href="http://ltt.polymtl.ca/svn/trunk/lttv/doc/developer/ust.html">LTTng User-space Tracing
 537 Design</a>. This new infrastructure is not yet implemented.
 538
 539 <p>
 540 The easy quick-and-dirty way to perform userspace tracing is currently to write
 541 an string to /mnt/debugfs/ltt/write_event. See <a
 542 href="#userspacetracing">Userspace tracing</a> in the
 543 installation for sources section of this document.
 544
 545 <hr />
 546
 547 <h2><a href="#TOCsection4" name="section4">Creating Debian or RPM packages</a></h2>
 548 <p>
 549
 550 <h3><a href="#TOCpkgdebian" name="pkgdebian">Create custom LTTV Debian packages</a></h3>
 551
 552 <PRE>
 553 Use : dpkg-buildpackage -rfakeroot
 554 </PRE>
 555 <p>
 556 You should then have your LTTV .deb files created for your architecture.
 557
 558 <h3><a href="#TOCpkglttng" name="pkglttng">Create custom LTTng packages</a></h3>
 559 <p>
 560 For building LTTng Debian packages :
 561 get the build tree with patches applies as explained in section 2.
 562
 563 <PRE>
 564 make menuconfig (or xconfig or config) (customize your configuration)
 565 make-kpkg kernel_image
 566 </PRE>
 567 <p>
 568 You will then see your freshly created .deb in /usr/src. Install it with
 569 <PRE>
 570 dpkg -i /usr/src/(image-name).deb
 571 </PRE>
 572 <p>
 573 Then, follow the section "Editing the system wide configuration" in section 2.
 574
 575 <hr />
 576
 577   </body>
 578 </html>