lttng(1) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | COMMANDS | ENVIRONMENT VARIABLES | FILES | EXIT STATUS | BUGS | RESOURCES | COPYRIGHTS | THANKS | AUTHORS | SEE ALSO | COLOPHON

LTTNG(1)                      LTTng Manual                      LTTNG(1)

NAME         top

       lttng - LTTng 2 tracer control command-line tool

SYNOPSIS         top

       lttng [--group=GROUP] [--mi=TYPE] [--no-sessiond | --sessiond-path=PATH]
             [--quiet | -v | -vv | -vvv] COMMAND [COMMAND OPTIONS]

DESCRIPTION         top

       The Linux Trace Toolkit: next generation <https://lttng.org/> is
       an open source software package used for correlated tracing of
       the Linux kernel, user applications, and user libraries.

       LTTng consists of Linux kernel modules (for Linux kernel tracing)
       and dynamically loaded libraries (for user application and
       library tracing).

       An LTTng session daemon, lttng-sessiond(8), receives commands
       from the command-line interface lttng to control the LTTng
       tracers. All interactions with the LTTng tracers happen through
       the lttng tool or through the liblttng-ctl library shipped with
       the LTTng-tools package.

       A tracing domain is a tracer category. There are five available
       domains. For some commands, the domain needs to be specified with
       a command-line option. The domain options are:

       -j, --jul
           Apply command to the java.util.logging (JUL) domain.

       -k, --kernel
           Apply command to the Linux kernel domain.

       -l, --log4j
           Apply command to the Apache log4j 1.2
           <https://logging.apache.org/log4j/1.2/> (Java) domain.

       -p, --python
           Apply command to the Python <https://www.python.org/> domain.

       -u, --userspace
           Apply command to the user space domain (application using
           liblttng-ust directly; see lttng-ust(3)).

       The LTTng session daemon is a tracing registry which allows the
       user to interact with multiple tracers (kernel and user space)
       within the same container, a tracing session. Traces can be
       gathered from the Linux kernel and/or from instrumented
       applications (see lttng-ust(3)). You can aggregate and read the
       events of LTTng traces using babeltrace(1).

       To trace the Linux kernel, the session daemon needs to be running
       as root. LTTng uses a tracing group to allow specific users to
       interact with the root session daemon. The default tracing group
       name is tracing. You can use the --group option to set the
       tracing group name to use.

       Session daemons can coexist. You can have a session daemon
       running as user Alice that can be used to trace her applications
       alongside a root session daemon or a session daemon running as
       user Bob.

           Note
           It is highly recommended to start the session daemon at boot
           time for stable and long-term tracing.

       User applications instrumented with LTTng automatically register
       to the root session daemon and to user session daemons. This
       allows any session daemon to list the available traceable
       applications and event sources (see lttng-list(1)).

       By default, the lttng-create(1) command automatically spawns a
       user session daemon if none is currently running. The --no-
       sessiond general option can be set to avoid this.

OPTIONS         top

       -g GROUP, --group=GROUP
           Use GROUP as Unix tracing group (default: tracing).

       -m TYPE, --mi=TYPE
           Print the command’s result using the machine interface type
           TYPE instead of a human-readable output.

           Supported types: xml.

           The machine interface (MI) mode converts the traditional
           pretty-printing to a machine output syntax. The MI mode
           provides a change-resistant way to access information
           generated by the lttng command-line program.

           When using the MI mode, the data is printed to the standard
           output. Errors and warnings are printed on the standard error
           with the pretty-print default format.

           If any error occurs during the execution of a command, the
           return value of the command will be different than 0. In this
           case, lttng does NOT guarantee the syntax and data validity
           of the generated MI output.

           For the xml MI type, an XML schema definition (XSD) file used
           for validation is available: see the src/common/mi_lttng.xsd
           file in the LTTng-tools source tree.

       -n, --no-sessiond
           Do not automatically spawn a session daemon.

       -q, --quiet
           Suppress all messages, including warnings and errors.

       --sessiond-path=PATH
           Set the session daemon binary’s absolute path to PATH.

       -v, --verbose
           Increase verbosity.

           Three levels of verbosity are available, which are triggered
           by appending additional v letters to the option (that is, -vv
           and -vvv).

   Program information
       -h, --help
           Show help.

       --list-commands
           List available commands.

       --list-options
           List available general options.

       -V, --version
           Show version.

COMMANDS         top

       The following commands also have their own --help option.

   Tracing sessions
       lttng-create(1)
           Create a tracing session.

       lttng-destroy(1)
           Tear down tracing sessions.

       lttng-load(1)
           Load tracing session configurations.

       lttng-regenerate(1)
           Manage an LTTng tracing session’s data regeneration.

       lttng-save(1)
           Save tracing session configurations.

       lttng-set-session(1)
           Set current tracing session.

   Channels
       lttng-add-context(1)
           Add context fields to a channel.

       lttng-disable-channel(1)
           Disable tracing channels.

       lttng-enable-channel(1)
           Create or enable tracing channels.

   Event rules
       lttng-disable-event(1)
           Disable event rules.

       lttng-enable-event(1)
           Create or enable event rules.

   Status
       lttng-list(1)
           List tracing sessions, domains, channels, and events.

       lttng-status(1)
           Get the status of the current tracing session.

   Control
       lttng-snapshot(1)
           Snapshot buffers of current tracing session.

       lttng-start(1)
           Start tracing.

       lttng-stop(1)
           Stop tracing.

   Tracing session rotation
       lttng-disable-rotation(1)
           Unset a rotation schedule.

       lttng-enable-rotation(1)
           Set a rotation schedule.

       lttng-rotate(1)
           Archive a tracing session’s current trace chunk.

   Resource tracking
       lttng-track(1)
           Track specific system resources.

       lttng-untrack(1)
           Untrack specific system resources.

   Miscellaneous
       lttng-help(1)
           Display help information about a command.

       lttng-version(1)
           Show version information.

       lttng-view(1)
           Start trace viewer.

ENVIRONMENT VARIABLES         top

       LTTNG_ABORT_ON_ERROR
           Set to 1 to abort the process after the first error is
           encountered.

       LTTNG_HOME
           Overrides the $HOME environment variable. Useful when the
           user running the commands has a non-writable home directory.

       LTTNG_MAN_BIN_PATH
           Absolute path to the man pager to use for viewing help
           information about LTTng commands (using lttng-help(1) or
           lttng COMMAND --help).

       LTTNG_SESSION_CONFIG_XSD_PATH
           Path in which the session.xsd session configuration XML
           schema may be found.

       LTTNG_SESSIOND_PATH
           Full session daemon binary path.

           The --sessiond-path option has precedence over this
           environment variable.

       Note that the lttng-create(1) command can spawn an LTTng session
       daemon automatically if none is running. See lttng-sessiond(8)
       for the environment variables influencing the execution of the
       session daemon.

FILES         top

       $LTTNG_HOME/.lttngrc
           User LTTng runtime configuration.

           This is where the per-user current tracing session is stored
           between executions of lttng(1). The current tracing session
           can be set with lttng-set-session(1). See lttng-create(1) for
           more information about tracing sessions.

       $LTTNG_HOME/lttng-traces
           Default output directory of LTTng traces. This can be
           overridden with the --output option of the lttng-create(1)
           command.

       $LTTNG_HOME/.lttng
           User LTTng runtime and configuration directory.

       $LTTNG_HOME/.lttng/sessions
           Default location of saved user tracing sessions (see
           lttng-save(1) and lttng-load(1)).

       /usr/local/etc/lttng/sessions
           System-wide location of saved tracing sessions (see
           lttng-save(1) and lttng-load(1)).

           Note
           $LTTNG_HOME defaults to $HOME when not explicitly set.

EXIT STATUS         top

       0
           Success

       1
           Command error

       2
           Undefined command

       3
           Fatal error

       4
           Command warning (something went wrong during the command)

BUGS         top

       If you encounter any issue or usability problem, please report it
       on the LTTng bug tracker <https://bugs.lttng.org/projects/lttng-
       tools>.

RESOURCES         top

       •   LTTng project website <https://lttng.org>

       •   LTTng documentation <https://lttng.org/docs>

       •   Git repositories <http://git.lttng.org>

       •   GitHub organization <http://github.com/lttng>

       •   Continuous integration <http://ci.lttng.org/>

       •   Mailing list <http://lists.lttng.org> for support and
           development: lttng-dev@lists.lttng.org

       •   IRC channel <irc://irc.oftc.net/lttng>: #lttng on
           irc.oftc.net

COPYRIGHTS         top

       This program is part of the LTTng-tools project.

       LTTng-tools is distributed under the GNU General Public License
       version 2 <http://www.gnu.org/licenses/old-
       licenses/gpl-2.0.en.html>. See the LICENSE
       <https://github.com/lttng/lttng-tools/blob/master/LICENSE> file
       for details.

THANKS         top

       Special thanks to Michel Dagenais and the DORSAL laboratory
       <http://www.dorsal.polymtl.ca/> at École Polytechnique de
       Montréal for the LTTng journey.

       Also thanks to the Ericsson teams working on tracing which helped
       us greatly with detailed bug reports and unusual test cases.

AUTHORS         top

       LTTng-tools was originally written by Mathieu Desnoyers, Julien
       Desfossez, and David Goulet. More people have since contributed
       to it.

       LTTng-tools is currently maintained by Jérémie Galarneau
       <mailto:jeremie.galarneau@efficios.com>.

SEE ALSO         top

       lttng-sessiond(8), lttng-relayd(8), lttng-crash(1), lttng-ust(3),
       babeltrace(1)

COLOPHON         top

       This page is part of the LTTng-Tools (    LTTng tools) project.
       Information about the project can be found at 
       ⟨http://lttng.org/⟩.  It is not known how to report bugs for this
       man page; if you know, please send a mail to man-pages@man7.org.
       This page was obtained from the project's upstream Git repository
       ⟨git://git.lttng.org/lttng-tools.git⟩ on 2019-11-19.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2019-11-14.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

LTTng 2.12.0-pre               10/29/2018                       LTTNG(1)

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