doc/man/lttng.1.txt

   1 lttng(1)
   2 ========
   3
   4
   5 NAME
   6 ----
   7 lttng - LTTng 2 tracer control command-line tool
   8
   9
  10 SYNOPSIS
  11 --------
  12 [verse]
  13 *lttng* [option:--group='GROUP'] [option:--mi='TYPE'] [option:--no-sessiond | option:--sessiond-path='PATH']
  14       [option:--quiet | option:-v | option:-vv | option:-vvv] '<<commands,COMMAND>>' ['COMMAND OPTIONS']
  15
  16
  17 DESCRIPTION
  18 -----------
  19 The http://lttng.org/[_Linux Trace Toolkit: next generation_] is an open
  20 source software package used for correlated tracing of the Linux kernel,
  21 user applications, and user libraries.
  22
  23 LTTng consists of Linux kernel modules (for Linux kernel tracing) and
  24 dynamically loaded libraries (for user application and library tracing).
  25
  26 An LTTng _session daemon_, linklttng:lttng-sessiond(8), receives
  27 commands from the command-line interface `lttng` to control the LTTng
  28 tracers. All interactions with the LTTng tracers happen through the
  29 `lttng` tool or through the liblttng-ctl library shipped with the
  30 LTTng-tools package.
  31
  32 A _tracing domain_ is a tracer category. There are five available
  33 domains. For some commands, the domain needs to be specified with a
  34 command-line option. The domain options are:
  35
  36 nloption:-j, nloption:--jul::
  37     Apply command to the `java.util.logging` (JUL) domain.
  38
  39 nloption:-k, nloption:--kernel::
  40     Apply command to the Linux kernel domain.
  41
  42 nloption:-l, nloption:--log4j::
  43     Apply command to the Apache log4j 1.2 (Java) domain.
  44
  45 nloption:-p, nloption:--python::
  46     Apply command to the Python domain.
  47
  48 nloption:-u, nloption:--userspace::
  49     Apply command to the user space domain.
  50
  51 The LTTng session daemon is a tracing registry which allows the user to
  52 interact with multiple tracers (kernel and user space) within the same
  53 container, a _tracing session_. Traces can be gathered from the Linux
  54 kernel and/or from instrumented applications (see
  55 linklttng:lttng-ust(3)). You can aggregate and read the events of LTTng
  56 traces using linklttng:babeltrace(1).
  57
  58 To trace the Linux kernel, the session daemon needs to be running as
  59 `root`. LTTng uses a _tracing group_ to allow specific users to interact
  60 with the root session daemon. The default tracing group name is
  61 `tracing`. You can use the option:--group option to set the tracing
  62 group name to use.
  63
  64 Session daemons can coexist. You can have a session daemon running as
  65 user Alice that can be used to trace her applications alongside a root
  66 session daemon or a session daemon running as user Bob.
  67
  68 NOTE: It is highly recommended to start the session daemon at boot time
  69 for stable and long-term tracing.
  70
  71 User applications instrumented with LTTng automatically register to the
  72 root session daemon and to user session daemons. This allows any session
  73 daemon to list the available traceable applications and event sources
  74 (see linklttng:lttng-list(1)).
  75
  76 By default, the linklttng:lttng-create(1) command automatically spawns a
  77 user session daemon if none is currently running. The
  78 option:--no-sessiond general option can be set to avoid this.
  79
  80
  81 OPTIONS
  82 -------
  83 option:-g, option:--group='GROUP'::
  84     Use 'GROUP' as Unix tracing group (default: `tracing`).
  85
  86 option:-m, option:--mi='TYPE'::
  87     Print the command's result using the machine interface type 'TYPE'
  88     instead of a human-readable output.
  89 +
  90 Supported types: `xml`.
  91 +
  92 The machine interface (MI) mode converts the traditional pretty-printing
  93 to a machine output syntax. The MI mode provides a change-resistant way
  94 to access information generated by the `lttng` command-line program.
  95 +
  96 When using the MI mode, the data is printed to the standard output.
  97 Errors and warnings are printed on the standard error with the
  98 pretty-print default format.
  99 +
 100 If any error occurs during the execution of a command, the return value
 101 of the command will be different than 0. In this case, `lttng` does
 102 :not: guarantee the syntax and data validity of the generated MI output.
 103 +
 104 For the `xml` MI type, an XML schema definition (XSD) file used for
 105 validation is available: see the `src/common/mi_lttng.xsd` file in
 106 the LTTng-tools source tree.
 107
 108 option:-n, option:--no-sessiond::
 109     Do not automatically spawn a session daemon.
 110
 111 option:-q, option:--quiet::
 112     Suppress all messages, including warnings and errors.
 113
 114 option:--sessiond-path='PATH'::
 115     Set the session daemon binary's absolute path to 'PATH'.
 116
 117 option:-v, option:--verbose::
 118     Increase verbosity.
 119 +
 120 Three levels of verbosity are available, which are triggered by
 121 appending additional `v` letters to the option
 122 (that is, `-vv` and `-vvv`).
 123
 124
 125 Program information
 126 ~~~~~~~~~~~~~~~~~~~
 127 option:-h, option:--help::
 128     Show help.
 129
 130 option:--list-commands::
 131     List available commands.
 132
 133 option:--list-options::
 134     List available general options.
 135
 136 option:-V, option:--version::
 137     Show version.
 138
 139
 140 [[commands]]
 141 COMMANDS
 142 --------
 143 The following commands also have their own nloption:--help option.
 144
 145
 146 Tracing sessions
 147 ~~~~~~~~~~~~~~~~
 148 linklttng:lttng-create(1)::
 149     Create a tracing session.
 150
 151 linklttng:lttng-destroy(1)::
 152     Tear down tracing sessions.
 153
 154 linklttng:lttng-load(1)::
 155     Load tracing session configurations.
 156
 157 linklttng:lttng-metadata(1)::
 158     Manage an LTTng tracing session's metadata generation.
 159
 160 linklttng:lttng-save(1)::
 161     Save tracing session configurations.
 162
 163 linklttng:lttng-set-session(1)::
 164     Set current tracing session.
 165
 166
 167 Channels
 168 ~~~~~~~~
 169 linklttng:lttng-add-context(1)::
 170     Add context fields to a channel.
 171
 172 linklttng:lttng-disable-channel(1)::
 173     Disable tracing channels.
 174
 175 linklttng:lttng-enable-channel(1)::
 176     Create or enable tracing channels.
 177
 178
 179 Event rules
 180 ~~~~~~~~~~~
 181 linklttng:lttng-disable-event(1)::
 182     Disable event rules.
 183
 184 linklttng:lttng-enable-event(1)::
 185     Create or enable event rules.
 186
 187
 188 Status
 189 ~~~~~~
 190 linklttng:lttng-list(1)::
 191     List tracing sessions, domains, channels, and events.
 192
 193 linklttng:lttng-status(1)::
 194     Get the status of the current tracing session.
 195
 196
 197 Control
 198 ~~~~~~~
 199 linklttng:lttng-snapshot(1)::
 200     Snapshot buffers of current tracing session.
 201
 202 linklttng:lttng-start(1)::
 203     Start tracing.
 204
 205 linklttng:lttng-stop(1)::
 206     Stop tracing.
 207
 208
 209 Resource tracking
 210 ~~~~~~~~~~~~~~~~~
 211 linklttng:lttng-track(1)::
 212     Track specific system resources.
 213
 214 linklttng:lttng-untrack(1)::
 215     Untrack specific system resources.
 216
 217
 218 Miscellaneous
 219 ~~~~~~~~~~~~~
 220 linklttng:lttng-calibrate(1)::
 221     Quantify LTTng overhead.
 222
 223 linklttng:lttng-help(1)::
 224     Display help information about a command.
 225
 226 linklttng:lttng-version(1)::
 227     Show version information.
 228
 229 linklttng:lttng-view(1)::
 230     Start trace viewer.
 231
 232
 233 include::common-cmd-footer.txt[]
 234
 235
 236 SEE ALSO
 237 --------
 238 linklttng:lttng-sessiond(8),
 239 linklttng:lttng-relayd(8),
 240 linklttng:lttng-crash(1),
 241 linklttng:lttng-ust(3),
 242 linklttng:babeltrace(1)