1LTTNG-START(1) LTTng Manual LTTNG-START(1)
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6 lttng-start - Start LTTng tracers
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9 lttng [GENERAL OPTIONS] start [SESSION]
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12 The lttng start command starts the various LTTng tracers for a given
13 inactive tracing session.
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15 Starting the LTTng tracers has the effect that all enabled event rules
16 within enabled channels can make their target event sources emit trace
17 events. Whether they are recorded to the local file system, sent over
18 the network, or not recorded at all depends on the specific
19 configuration of the tracing session in which tracing is started. See
20 lttng-create(1) for different session modes.
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22 A tracing session with running tracers is said to be active. Active
23 tracing sessions can return to the inactive state using the lttng-
24 stop(1) command.
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26 If SESSION is omitted, the LTTng tracers are started for the current
27 tracing session (see lttng-create(1) for more information about the
28 current tracing session). Otherwise, they are started for the existing
29 tracing session named SESSION. lttng list outputs all the existing
30 tracing sessions (see lttng-list(1)).
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33 General options are described in lttng(1).
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35 Program information
36 -h, --help
37 Show command help.
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39 This option, like lttng-help(1), attempts to launch /usr/bin/man to
40 view the command’s man page. The path to the man pager can be
41 overridden by the LTTNG_MAN_BIN_PATH environment variable.
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43 --list-options
44 List available command options.
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47 LTTNG_ABORT_ON_ERROR
48 Set to 1 to abort the process after the first error is encountered.
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50 LTTNG_HOME
51 Overrides the $HOME environment variable. Useful when the user
52 running the commands has a non-writable home directory.
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54 LTTNG_MAN_BIN_PATH
55 Absolute path to the man pager to use for viewing help information
56 about LTTng commands (using lttng-help(1) or lttng COMMAND --help).
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58 LTTNG_SESSION_CONFIG_XSD_PATH
59 Path in which the session.xsd session configuration XML schema may
60 be found.
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62 LTTNG_SESSIOND_PATH
63 Full session daemon binary path.
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65 The --sessiond-path option has precedence over this environment
66 variable.
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68 Note that the lttng-create(1) command can spawn an LTTng session daemon
69 automatically if none is running. See lttng-sessiond(8) for the
70 environment variables influencing the execution of the session daemon.
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73 $LTTNG_HOME/.lttngrc
74 User LTTng runtime configuration.
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76 This is where the per-user current tracing session is stored
77 between executions of lttng(1). The current tracing session can be
78 set with lttng-set-session(1). See lttng-create(1) for more
79 information about tracing sessions.
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81 $LTTNG_HOME/lttng-traces
82 Default output directory of LTTng traces. This can be overridden
83 with the --output option of the lttng-create(1) command.
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85 $LTTNG_HOME/.lttng
86 User LTTng runtime and configuration directory.
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88 $LTTNG_HOME/.lttng/sessions
89 Default location of saved user tracing sessions (see lttng-save(1)
90 and lttng-load(1)).
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92 /usr/local/etc/lttng/sessions
93 System-wide location of saved tracing sessions (see lttng-save(1)
94 and lttng-load(1)).
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96 Note
97 $LTTNG_HOME defaults to $HOME when not explicitly set.
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100 0
101 Success
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103 1
104 Command error
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106 2
107 Undefined command
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109 3
110 Fatal error
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112 4
113 Command warning (something went wrong during the command)
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116 If you encounter any issue or usability problem, please report it on
117 the LTTng bug tracker <https://bugs.lttng.org/projects/lttng-tools>.
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120 · LTTng project website <https://lttng.org>
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122 · LTTng documentation <https://lttng.org/docs>
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124 · Git repositories <http://git.lttng.org>
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126 · GitHub organization <http://github.com/lttng>
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128 · Continuous integration <http://ci.lttng.org/>
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130 · Mailing list <http://lists.lttng.org> for support and development:
131 lttng-dev@lists.lttng.org
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133 · IRC channel <irc://irc.oftc.net/lttng>: #lttng on irc.oftc.net
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136 This program is part of the LTTng-tools project.
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138 LTTng-tools is distributed under the GNU General Public License version
139 2 <http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html>. See the
140 LICENSE <https://github.com/lttng/lttng-tools/blob/master/LICENSE> file
141 for details.
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144 Special thanks to Michel Dagenais and the DORSAL laboratory
145 <http://www.dorsal.polymtl.ca/> at École Polytechnique de Montréal for
146 the LTTng journey.
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148 Also thanks to the Ericsson teams working on tracing which helped us
149 greatly with detailed bug reports and unusual test cases.
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152 lttng-stop(1), lttng(1)
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156LTTng 2.11.1 7 April 2016 LTTNG-START(1)