lttng-untrack(1) (v2.11)

lttng-untrack — Remove one or more entries from an LTTng resource tracker

lttng [GENERAL OPTIONS] untrack (--kernel | --userspace)
      [--session=SESSION] (--pid=PID[,PID]… | --all --pid)

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.

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] [ ] [ ]

General options are described in lttng(1).

One of:

-k, --kernel

Untrack resources tracked in the Linux kernel domain.

-u, --userspace

Untrack resources tracked in the user space domain.

-s, --session=SESSION

Untrack resources in the tracing session named SESSION instead of the current tracing session.

-a, --all

Used in conjunction with an empty --pid option: untrack all process IDs (clear the whitelist).

-p [PID[,PID]…], --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.

-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.

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.

$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)).

/etc/lttng/sessions

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

0

Success

1

Command error

2

Undefined command

3

Fatal error

4

Command warning (something went wrong during the command)

If you encounter any issue or usability problem, please report it on the LTTng bug tracker.

• LTTng project website

• LTTng documentation

• Git repositories

• GitHub organization

• Continuous integration

• Mailing list for support and development: lttng-dev@lists.lttng.org

• IRC channel: #lttng on irc.oftc.net

This program is part of the LTTng-tools project.

LTTng-tools is distributed under the GNU General Public License version 2. See the LICENSE file for details.

Special thanks to Michel Dagenais and the DORSAL laboratory 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.

lttng-track(1), lttng(1)