SYNOPSIS
lttng [GENERAL OPTIONS] untrack (--kernel | --userspace)
[--session=SESSION] (--pid=PID[,PID]... | --all --pid)
DESCRIPTION
The lttng untrack commands removes one or more entries from a resource tracker.
See lttng-track(1) to learn more about LTTng trackers.
The untrack command removes specific resources from a tracker. The resources to remove must have been precedently added by lttng-track(1). It is also possible to remove all the resources from the whitelist using the --all option.
As of this version, the only available tracker is the PID tracker.
Example
One common operation is to create a tracing session (see lttng-create(1)), remove all the entries from the PID tracker whitelist, start tracing, and then manually track PIDs while tracing is active.
Assume the maximum system PID is 7 for this example.
Command:
-
lttng create
Initial whitelist:
-
[0] [1] [2] [3] [4] [5] [6] [7]
Command:
-
lttng untrack --userspace --pid --all
Whitelist:
-
[ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ]
Commands:
-
lttng enable-event --userspace ... lttng start # ... lttng track --userspace --pid=3,5
Whitelist:
-
[ ] [ ] [ ] [3] [ ] [5] [ ] [ ]
Command:
-
lttng track --userspace --pid=2
Whitelist:
-
[ ] [ ] [2] [3] [ ] [5] [ ] [ ]
OPTIONS
General options are described in lttng(1).
Domain
One of:
-k, --kernel
- Untrack resources tracked in the Linux kernel domain.
-u, --userspace
- Untrack resources tracked in the user space domain.
Target
-s, --session=SESSION
- Untrack resources in the tracing session named SESSION instead of the current tracing session.
Untracking
-a, --all
- Used in conjunction with an empty --pid option: untrack all process IDs (clear the whitelist).
-p, --pid[=PID[,PID]...]
-
Untrack process IDs
PID
(remove them from the current whitelist).
The PID argument must be omitted when also using the --all option.
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.
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: [email protected]
- • 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:[email protected]>.