doc/man/lttng.1.txt

   1 lttng(1)
   2 ========
   3 :revdate: 16 October 2019
   4
   5
   6 NAME
   7 ----
   8 lttng - LTTng 2 tracer control command-line tool
   9
  10
  11 SYNOPSIS
  12 --------
  13 [verse]
  14 *lttng* [option:--group='GROUP'] [option:--mi='TYPE'] [option:--no-sessiond | option:--sessiond-path='PATH']
  15       [option:--quiet | option:-v | option:-vv | option:-vvv] '<<commands,COMMAND>>' ['COMMAND OPTIONS']
  16
  17
  18 DESCRIPTION
  19 -----------
  20 The https://lttng.org/[_Linux Trace Toolkit: next generation_] is an open
  21 source software package used for correlated tracing of the Linux kernel,
  22 user applications, and user libraries.
  23
  24 LTTng consists of Linux kernel modules (for Linux kernel tracing) and
  25 dynamically loaded libraries (for user application and library tracing).
  26
  27 An LTTng _session daemon_, man:lttng-sessiond(8), receives
  28 commands from the command-line interface `lttng` to control the LTTng
  29 tracers. All interactions with the LTTng tracers happen through the
  30 `lttng` tool or through the liblttng-ctl library shipped with the
  31 LTTng-tools package.
  32
  33 A _tracing domain_ is a tracer category. There are five available
  34 domains. For some commands, the domain needs to be specified with a
  35 command-line option. The domain options are:
  36
  37 nloption:-j, nloption:--jul::
  38     Apply command to the `java.util.logging` (JUL) domain.
  39
  40 nloption:-k, nloption:--kernel::
  41     Apply command to the Linux kernel domain.
  42
  43 nloption:-l, nloption:--log4j::
  44     Apply command to the https://logging.apache.org/log4j/1.2/[Apache log4j 1.2]
  45     (Java) domain.
  46
  47 nloption:-p, nloption:--python::
  48     Apply command to the https://www.python.org/[Python] domain.
  49
  50 nloption:-u, nloption:--userspace::
  51     Apply command to the user space domain (application using
  52     liblttng-ust directly; see man:lttng-ust(3)).
  53
  54 The LTTng session daemon is a tracing registry which allows the user to
  55 interact with multiple tracers (kernel and user space) within the same
  56 container, a _tracing session_. Traces can be gathered from the Linux
  57 kernel and/or from instrumented applications (see
  58 man:lttng-ust(3)). You can aggregate and read the events of LTTng
  59 traces using man:babeltrace2(1).
  60
  61 To trace the Linux kernel, the session daemon needs to be running as
  62 `root`. LTTng uses a _tracing group_ to allow specific users to interact
  63 with the root session daemon. The default tracing group name is
  64 `tracing`. You can use the option:--group option to set the tracing
  65 group name to use.
  66
  67 Session daemons can coexist. You can have a session daemon running as
  68 user Alice that can be used to trace her applications alongside a root
  69 session daemon or a session daemon running as user Bob.
  70
  71 NOTE: It is highly recommended to start the session daemon at boot time
  72 for stable and long-term tracing.
  73
  74 User applications instrumented with LTTng automatically register to the
  75 root session daemon and to user session daemons. This allows any session
  76 daemon to list the available traceable applications and event sources
  77 (see man:lttng-list(1)).
  78
  79 By default, the man:lttng-create(1) command automatically spawns a
  80 user session daemon if none is currently running. The
  81 option:--no-sessiond general option can be set to avoid this.
  82
  83
  84 OPTIONS
  85 -------
  86 option:-g 'GROUP', option:--group='GROUP'::
  87     Use 'GROUP' as Unix tracing group (default: `tracing`).
  88
  89 option:-m 'TYPE', option:--mi='TYPE'::
  90     Print the command's result using the machine interface type 'TYPE'
  91     instead of a human-readable output.
  92 +
  93 Supported types: `xml`.
  94 +
  95 The machine interface (MI) mode converts the traditional pretty-printing
  96 to a machine output syntax. The MI mode provides a change-resistant way
  97 to access information generated by the `lttng` command-line program.
  98 +
  99 When using the MI mode, the data is printed to the standard output.
 100 Errors and warnings are printed on the standard error with the
 101 pretty-print default format.
 102 +
 103 If any error occurs during the execution of a command, the return value
 104 of the command will be different than 0. In this case, `lttng` does
 105 :not: guarantee the syntax and data validity of the generated MI output.
 106 +
 107 For the `xml` MI type, an XML schema definition (XSD) file used for
 108 validation is available: see the `src/common/mi_lttng.xsd` file in
 109 the LTTng-tools source tree.
 110
 111 option:-n, option:--no-sessiond::
 112     Do not automatically spawn a session daemon.
 113
 114 option:-q, option:--quiet::
 115     Suppress all messages, including warnings and errors.
 116
 117 option:--sessiond-path='PATH'::
 118     Set the session daemon binary's absolute path to 'PATH'.
 119
 120 option:-v, option:--verbose::
 121     Increase verbosity.
 122 +
 123 Three levels of verbosity are available, which are triggered by
 124 appending additional `v` letters to the option
 125 (that is, `-vv` and `-vvv`).
 126
 127
 128 Program information
 129 ~~~~~~~~~~~~~~~~~~~
 130 option:-h, option:--help::
 131     Show help.
 132
 133 option:--list-commands::
 134     List available commands.
 135
 136 option:--list-options::
 137     List available general options.
 138
 139 option:-V, option:--version::
 140     Show version.
 141
 142
 143 [[commands]]
 144 COMMANDS
 145 --------
 146 The following commands also have their own nloption:--help option.
 147
 148
 149 Tracing sessions
 150 ~~~~~~~~~~~~~~~~
 151 man:lttng-create(1)::
 152     {cmd_descr_create}.
 153
 154 man:lttng-destroy(1)::
 155     {cmd_descr_destroy}.
 156
 157 man:lttng-load(1)::
 158     {cmd_descr_load}.
 159
 160 man:lttng-regenerate(1)::
 161     {cmd_descr_regenerate}.
 162
 163 man:lttng-save(1)::
 164     {cmd_descr_save}.
 165
 166 man:lttng-set-session(1)::
 167     {cmd_descr_set_session}.
 168
 169
 170 Channels
 171 ~~~~~~~~
 172 man:lttng-add-context(1)::
 173     {cmd_descr_add_context}.
 174
 175 man:lttng-disable-channel(1)::
 176     {cmd_descr_disable_channel}.
 177
 178 man:lttng-enable-channel(1)::
 179     {cmd_descr_enable_channel}.
 180
 181
 182 Event rules
 183 ~~~~~~~~~~~
 184 man:lttng-disable-event(1)::
 185     {cmd_descr_disable_event}.
 186
 187 man:lttng-enable-event(1)::
 188     {cmd_descr_enable_event}.
 189
 190
 191 Status
 192 ~~~~~~
 193 man:lttng-list(1)::
 194     {cmd_descr_list}.
 195
 196 man:lttng-status(1)::
 197     {cmd_descr_status}.
 198
 199
 200 Control
 201 ~~~~~~~
 202 man:lttng-snapshot(1)::
 203     {cmd_descr_snapshot}.
 204
 205 man:lttng-start(1)::
 206     {cmd_descr_start}.
 207
 208 man:lttng-stop(1)::
 209     {cmd_descr_stop}.
 210
 211
 212 Tracing session rotation
 213 ~~~~~~~~~~~~~~~~~~~~~~~~
 214 man:lttng-disable-rotation(1)::
 215     {cmd_descr_disable_rotation}.
 216
 217 man:lttng-enable-rotation(1)::
 218     {cmd_descr_enable_rotation}.
 219
 220 man:lttng-rotate(1)::
 221     {cmd_descr_rotate}.
 222
 223
 224
 225 Resource tracking
 226 ~~~~~~~~~~~~~~~~~
 227 man:lttng-track(1)::
 228     {cmd_descr_track}.
 229
 230 man:lttng-untrack(1)::
 231     {cmd_descr_untrack}.
 232
 233
 234 Miscellaneous
 235 ~~~~~~~~~~~~~
 236 man:lttng-help(1)::
 237     {cmd_descr_help}.
 238
 239 man:lttng-version(1)::
 240     {cmd_descr_version}.
 241
 242 man:lttng-view(1)::
 243     {cmd_descr_view}.
 244
 245
 246 include::common-cmd-footer.txt[]
 247
 248
 249 SEE ALSO
 250 --------
 251 man:lttng-sessiond(8),
 252 man:lttng-relayd(8),
 253 man:lttng-crash(1),
 254 man:lttng-ust(3),
 255 man:babeltrace2(1)