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LTTNG-REGENERATE(1) LTTng Manual LTTNG-REGENERATE(1)

NAME

lttng-regenerate - Manage an LTTng tracing session's data regeneration

SYNOPSIS

Regenerate the metadata of a session: 

lttng [GENERAL OPTIONS] regenerate metadata [--session=SESSION]

Regenerate the state dump of a session:

lttng [GENERAL OPTIONS] regenerate statedump [--session=SESSION]

DESCRIPTION

The lttng regenerate command regenerates specific data of a tracing session.

As of this version, the metadata and statedump actions are available.

Regenerating a tracing session’s metadata

The lttng regenerate metadata action can be used to resample the offset between the system’s monotonic clock and the wall-clock time.

This action is meant to be used to resample the wall-clock time following a major NTP <https://en.wikipedia.org/wiki/Network_Time_Protocol> correction. As such, a system booting with an incorrect wall time can be traced before its wall time is NTP-corrected. Regenerating the tracing session’s metadata ensures that trace viewers can accurately determine the events time relative to Unix Epoch.

Regenerating a tracing session’s state dump

The lttng regenerate statedump action can be used to collect up-to-date state dump information during the tracing session. This is particularly useful in snapshot (see lttng-snapshot(1)) or trace file rotation (see lttng-enable-channel(1)) modes where the state dump information may be lost.

OPTIONS

General options are described in lttng(1).

-s SESSION, --session=SESSION

Regenerate the data of the tracing session named SESSION instead of the current tracing session.

Program information

-h, --help
Show command help.

This option, like lttng-help(1), attempts to launch /usr/bin/man to view the command’s man page. The path to the man pager can be overridden by the LTTNG_MAN_BIN_PATH environment variable.

--list-options

List available command options.

LIMITATIONS

The lttng regenerate metadata command can only be used on kernel and user space tracing sessions (using per-user buffering), in non-live mode.

See lttng-enable-channel(1) for more information about buffering schemes and lttng-create(1) for more information about the different tracing session modes.

ENVIRONMENT VARIABLES

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

$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

0
Success

1

Command error

2

Undefined command

3

Fatal error

4

Command warning (something went wrong during the command)

BUGS

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

RESOURCES

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

•LTTng documentation <http://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

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

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

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

lttng(1)
01/22/2019 LTTng 2.10.6