trunk/lttv/QUICKSTART

   1 Linux Trace Toolkit Quickstart
   2 ------------------------------
   3 Author : Mathieu Desnoyers, September 2005
   4 Last update : July 31, 2008
   5
   6
   7 This document is made of four parts : the first one explains how to install
   8 LTTng and LTTV from Debian and RPM binary packages, the second one explains how
   9 to install LTTng and LTTV from sources and the third one describes the steps
  10 to follow to trace a system and view it. The fourth and last part explains
  11 briefly how to add a new trace point to the kernel and to user space
  12 applications.
  13
  14 What you will typically want is to read sections 2 and 3 : install LTTng from
  15 sources and use it.
  16
  17 These operations are made for installing the LTTng 0.12 tracer on a linux 2.6.X
  18 kernel. You will also find instructions for installation of LTTV 0.8.x : the
  19 Linux Trace Toolkit Viewer.
  20
  21 To see the list of compatibilities between LTTng, ltt-control, LTTV and
  22 markers-userspace, please refer to :
  23 http://ltt.polymtl.ca > LTTng+LTTV versions compatibility
  24
  25
  26
  27 The following lttng patch is necessary to have the tracing hooks in the kernel.
  28 The following ltt-control module controls the tracing.
  29
  30 Required programs and libraries are assumed to be automatically installed in an
  31 installation with Debian or RPM packages. In the case of an installation from
  32 sources, the dependencies are listed.
  33
  34
  35 ** Current development status **
  36
  37 LTTng :
  38 supported architectures :
  39 Intel Pentium (UP/SMP) with TSC
  40 PowerPC 32 and 64 bits
  41 ARM
  42 x86_64
  43 C2 Microsystems (variant of MIPS)
  44
  45 LTTV :
  46 supported architectures :
  47 Intel i386 and better
  48 Intel 64 bits
  49 PowerPC 32 and 64 bits
  50
  51
  52 ***********************************************************
  53 ** Section 1 * Installation from Debian or RPM packages  **
  54 ***********************************************************
  55
  56 * Create custom LTTV Debian packages
  57
  58 Use : dpkg-buildpackage -rfakeroot
  59
  60 You should then have your LTTV .deb files created for your architecture.
  61
  62 * Create custom LTTng packages
  63
  64 For building LTTng Debian packages :
  65
  66 Get the build tree with patches applies as explained in section 2.
  67
  68 make menuconfig (or xconfig or config) (customize your configuration)
  69 make-kpkg kernel_image
  70
  71 You will then see your freshly created .deb in /usr/src. Install it with
  72 dpkg -i /usr/src/(image-name).deb
  73
  74 Then, follow the section "Editing the system wide configuration" in section 2.
  75
  76
  77 ***********************************************************
  78 ** Section 2 * Installation from sources                 **
  79 ***********************************************************
  80
  81 * Prerequisites
  82
  83 Tools needed to follow the package download steps :
  84
  85 o wget
  86 o bzip2
  87 o gzip
  88 o tar
  89
  90 You have to install the standard development libraries and programs necessary
  91 to compile a kernel :
  92
  93 (from Documentation/Changes in the Linux kernel tree)
  94 o  Gnu C                  2.95.3                  # gcc --version
  95 o  Gnu make               3.79.1                  # make --version
  96 o  binutils               2.12                    # ld -v
  97 o  util-linux             2.10o                   # fdformat --version
  98 o  module-init-tools      0.9.10                  # depmod -V
  99
 100 You might also want to have libncurses5 to have the text mode kernel
 101 configuration menu, but there are alternatives.
 102
 103 Prerequisites for LTTV 0.x.x installation are :
 104
 105 gcc 3.2 or better
 106 gtk 2.4 or better development libraries
 107   (Debian : libgtk2.0, libgtk2.0-dev)
 108   (Fedora : gtk2, gtk2-devel)
 109   note : For Fedora users : this might require at least core 3 from Fedora,
 110   or you might have to compile your own GTK2 library.
 111 glib 2.4 or better development libraries
 112   (Debian : libglib2.0-0, libglib2.0-dev)
 113   (Fedora : glib2, glib2-devel)
 114 libpopt development libraries
 115   (Debian : libpopt0, libpopt-dev)
 116   (Fedora : popt)
 117 libpango development libraries
 118   (Debian : libpango1.0, libpango1.0-dev)
 119   (Fedora : pango, pango-devel)
 120 libc6 development librairies
 121   (Debian : libc6, libc6-dev)
 122   (Fedora : glibc, glibc)
 123
 124 * Reminder
 125
 126 See the list of compatibilities between LTTng, ltt-control, LTTV and
 127 markers-userspace at :
 128 http://ltt.polymtl.ca > LTTng+LTTV versions compatibility
 129
 130
 131
 132 * Getting the LTTng packages
 133
 134 su -
 135 mkdir /usr/src/lttng
 136 cd /usr/src/lttng
 137 (see http://ltt.polymtl.ca/lttng for package listing)
 138 wget http://ltt.polymtl.ca/lttng/patch-2.6.X-lttng-0.x.xx.tar.bz2
 139 bzip2 -cd patch-2.6.X-lttng-0.x.xx.tar.bz2 | tar xvof -
 140
 141
 142 * Getting LTTng kernel sources
 143
 144 su -
 145 cd /usr/src
 146 wget http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.X.tar.bz2
 147 bzip2 -cd linux-2.6.X.tar.bz2 | tar xvof -
 148 cd linux-2.6.X
 149 - For LTTng 0.9.4- cat /usr/src/lttng/patch*-2.6.X-lttng-0.x.xx* | patch -p1
 150 - For LTTng 0.9.5+ apply the patches in the order specified in the series file,
 151   or use quilt
 152 cd ..
 153 mv linux-2.6.X linux-2.6.X-lttng-0.x.xx
 154
 155
 156 * Installing a LTTng kernel
 157
 158 su -
 159 cd /usr/src/linux-2.6.X-lttng-0.x.xx
 160 make menuconfig (or make xconfig or make config)
 161     Select the < Help > button if you are not familiar with kernel
 162     configuration.
 163     Items preceded by [*] means they has to be built into the kernel.
 164     Items preceded by [M] means they has to be built as modules.
 165     Items preceded by [ ] means they should be removed.
 166   go to the "General setup" section
 167     Select the following options :
 168     [*] Activate tracepoints
 169     [*] Activate markers
 170     [*] Activate userspace markers ABI
 171     <*> Compile generic tracing probes
 172     Linux Trace Toolkit  --->
 173     [LTTng fine-grained-timestamping]
 174     [*] Linux Trace Toolkit Instrumentation Support
 175     <M> or <*> Linux Trace Toolkit Relay+DebugFS Support
 176     <M> or <*> Linux Trace Toolkit Serializer
 177     <M> or <*> Linux Trace Toolkit Marker Control
 178     <M> or <*> Linux Trace Toolkit Tracer
 179       It makes no difference for the rest of the procedure whether the Tracer
 180       is compiled built-in or as a module.
 181     activate :
 182        [*] Align Linux Trace Toolkit Traces
 183        <M> Linux Trace Toolkit Netlink Controller
 184        <M> Linux Trace Toolkit State Dump
 185     your choice (see < Help >) :
 186        [ ] Write heartbeat event to shrink traces
 187        [ ] Support trace extraction from crash dump
 188   Select <Exit>
 189   Select <Exit>
 190   Select <Yes>
 191 make
 192 make modules_install
 193 (if necessary, create a initrd with mkinitrd or your preferate alternative)
 194 (mkinitrd -o /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx)
 195
 196 -- on X86, X86_64
 197 make install
 198 reboot
 199 Select the Linux 2.6.17-lttng-0.x.xx kernel in your boot loader.
 200
 201 -- on PowerPC
 202 cp vmlinux.strip /boot/vmlinux-2.6.X-lttng-0.x.xx
 203 cp System.map /boot/System.map-2.6.X-lttng-0.x.xx
 204 cp .config /boot/config-2.6.X-lttng-0.x.xx
 205 depmod -ae -F /boot/System.map-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
 206 mkinitrd /boot/initrd.img-2.6.X-lttng-0.x.xx 2.6.X-lttng-0.x.xx
 207 (edit /etc/yaboot.conf to add a new entry pointing to your kernel : the entry
 208 that comes first is the default kernel)
 209 ybin
 210 select the right entry at the yaboot prompt (see choices : tab, select : type
 211 the kernel name followed by enter)
 212 Select the Linux 2.6.17-lttng-0.x.xx kernel in your boot loader.
 213 --
 214
 215
 216
 217 * Editing the system wide configuration
 218
 219 You must activate debugfs and specify a mount point. This is typically done in
 220 fstab such that it happens at boot time.
 221
 222 If you have never used DebugFS before, these operation would do this for you :
 223
 224 mkdir /mnt/debugfs
 225 cp /etc/fstab /etc/fstab.lttng.bkp
 226 echo "debugfs         /mnt/debugfs    debugfs rw              0       0"  >> /etc/fstab
 227
 228 then, rebooting or issuing the following command will activate debugfs :
 229
 230 mount /mnt/debugfs
 231
 232 You need to load the LTT modules to be able to control tracing from user
 233 space. This is done by issuing the following commands. Note however
 234 these commands load all LTT modules. Depending on what options you chose to
 235 compile statically, you may not need to issue all these commands.
 236
 237 modprobe ltt-control
 238 modprobe ltt-marker-control
 239 modprobe ltt-tracer
 240 modprobe ltt-serialize
 241 modprobe ltt-relay
 242 modprobe ipc-trace
 243 modprobe kernel-trace
 244 modprobe mm-trace
 245 modprobe net-trace
 246 modprobe fs-trace
 247 modprobe syscall-trace
 248 #if locking tracing is wanted, uncomment the following
 249 #modprobe lockdep-trace
 250
 251 If you want to have complete information about the kernel state (including all
 252 the process names), you need to load the ltt-statedump module. This is done by
 253 issuing the command :
 254
 255 modprobe ltt-statedump
 256
 257 You can automate at boot time loading the ltt-control module by :
 258
 259 cp /etc/modules /etc/modules.bkp
 260 echo ltt-control >> /etc/modules
 261 echo ltt-marker-control >> /etc/modules
 262 echo ltt-tracer >> /etc/modules
 263 echo ltt-serialize >> /etc/modules
 264 echo ltt-relay >> /etc/modules
 265 echo ipc-trace >> /etc/modules
 266 echo kernel-trace >> /etc/modules
 267 echo mm-trace >> /etc/modules
 268 echo net-trace >> /etc/modules
 269 echo fs-trace >> /etc/modules
 270 #if locking tracing is wanted, uncomment the following
 271 #echo lockdep-trace >> /etc/modules
 272
 273
 274 * Getting and installing the ltt-control package (on the traced machine)
 275 (note : the ltt-control package contains lttd and lttctl. Although it has the
 276 same name as the ltt-control kernel module, they are *not* the same thing.)
 277 su -
 278 cd /usr/src
 279 wget http://ltt.polymtl.ca/lttng/ltt-control-0.x-xxxx2006.tar.gz
 280 gzip -cd ltt-control-0.x-xxxx2006.tar.gz | tar xvof -
 281 cd ltt-control-0.x-xxxx2006
 282 (refer to README to see the development libraries that must be installed on you
 283 system)
 284 ./configure
 285 make
 286 make install
 287
 288 * Getting and installing the markers-userspace package for user space tracing
 289 See http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2 or more recent.
 290
 291
 292 * Getting and installing the LTTV package (on the visualisation machine, same or
 293   different from the visualisation machine)
 294
 295 su -
 296 cd /usr/src
 297 wget http://ltt.polymtl.ca/packages/lttv-0.x.xx-xxxx2008.tar.gz
 298 gzip -cd lttv-0.x.xx-xxxx2008.tar.gz | tar xvof -
 299 cd lttv-0.x.xx-xxxx2008
 300 (refer to README to see the development libraries that must be installed on your
 301 system)
 302 ./configure
 303 make
 304 make install
 305
 306
 307
 308
 309 ***********************************************************
 310 ** Section 3 * Using LTTng and LTTV                      **
 311 ***********************************************************
 312
 313 * IMPORTANT : Arm Linux Kernel Markers after each boot
 314
 315 ltt-armall
 316
 317 * Use graphical LTTV to control tracing and analyse traces
 318
 319 lttv-gui (or /usr/local/bin/lttv-gui)
 320   - Spot the "Tracing Control" icon : click on it
 321       (it's a traffic light icon)
 322     - enter the root password
 323     - click "start"
 324     - click "stop"
 325     - Yes
 326       * You should now see a trace
 327
 328 * Use text mode LTTng to control tracing
 329
 330 The tracing can be controlled from a terminal by using the lttctl command (as
 331 root).
 332
 333 Start tracing :
 334
 335 lttctl -n trace -d -l /mnt/debugfs/ltt -t /tmp/trace
 336
 337 Stop tracing and destroy trace channels :
 338
 339 lttctl -n trace -R
 340
 341 see lttctl --help for details.
 342
 343 (note : to see if the buffers has been filled, look at the dmesg output after
 344 lttctl -R or after stopping tracing from the GUI, it will show an event lost
 345 count. If it is the case, try using larger buffers. See lttctl --help to learn
 346 how.)
 347
 348 * Use text mode LTTV
 349
 350 Feel free to look in /usr/local/lib/lttv/plugins to see all the text and
 351 graphical plugins available.
 352
 353 For example, a simple trace dump in text format is available with :
 354
 355 lttv -m textDump -t /tmp/trace
 356
 357 see lttv -m textDump --help for detailed command line options of textDump.
 358
 359 It is, in the current state of the project, very useful to use "grep" on the
 360 text output to filter by specific event fields. You can later copy the timestamp
 361 of the events to the clipboard and paste them in the GUI by clicking on the
 362 bottom right label "Current time". Support for this type of filtering should
 363 be added to the filter module soon.
 364
 365 * Hybrid mode
 366
 367 Starting from LTTng 0.5.105 and ltt-control 0.20, a new mode can be used :
 368 hybrid. It can be especially useful when studying big workloads on a long period
 369 of time.
 370
 371 When using this mode, the most important, low rate control information will be
 372 recorded during all the trace by lttd (i.e. process creation/exit). The high
 373 rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
 374 flight recorder buffer (now named flight-channelname_X).
 375
 376 The following lttctl commands take an hybrid trace :
 377
 378 Create trace channel, start lttd on normal channels, start tracing:
 379 lttctl -n tracename -d -l /mnt/debugfs/ltt -t /tmp/trace1 -m hybrid
 380
 381 Stop tracing, start lttd on flight recorder channels, destroy trace channels :
 382 lttctl -n tracename -f -l /mnt/debugfs/ltt -t /tmp/trace1 -m hybrid
 383
 384
 385 We will need to tweak what we consider "important" medium rate events. For
 386 instance, thread branding events are actually considered a "high rate" event
 387 when it should be considered "medium rate". The same should apply for the
 388 state dump process enumeration.
 389
 390 * Flight recorder mode
 391
 392 The flight recorder mode writes data into overwritten buffers for all channels,
 393 including control channels, except for the facilities tracefiles.
 394
 395 The following lttctl commands take a flight recorder trace :
 396
 397 lttctl -n trace -c -m flight
 398 lttd -n -d -t /tmp/trace -c /mnt/debugfs/ltt/trace
 399 lttctl -n trace -s
 400 .. do stuff
 401 lttctl -n trace -q
 402 lttd -f -d -t /tmp/trace -c /mnt/debugfs/ltt/trace
 403 lttctl -m trace -r
 404
 405
 406 **************************************************************
 407 ** Section 4 * Adding new instrumentations with the markers **
 408 **************************************************************
 409
 410 See Documentation/markers.txt and Documentation/tracepoints.txt in your kernel
 411 tree.
 412
 413 * Add new events to userspace programs with userspace markers
 414 http://ltt.polymtl.ca/packages/
 415
 416 Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
 417 allows inserting markers in executables and libraries, currently only on x86_32
 418 and x86_64.
 419