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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | ENVIRONMENT VARIABLES | FILES | EXIT STATUS | BUGS | RESOURCES | COPYRIGHTS | THANKS | AUTHORS | SEE ALSO | COLOPHON |
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LTTNG-TRACK(1) LTTng Manual LTTNG-TRACK(1)
lttng-track - Add one or more entries to an LTTng resource tracker
lttng [GENERAL OPTIONS] track (--kernel | --userspace)
[--session=SESSION] (--pid=PID[,PID]... | --all --pid)
The lttng track commands adds one or more entries to a resource
tracker.
A resource tracker is a whitelist of resources. Tracked resources
are allowed to emit events, provided those events are targeted by
enabled event rules (see lttng-enable-event(1)).
Tracker entries can be removed from the whitelist with
lttng-untrack(1).
As of this version, the only available tracker is the PID tracker.
The process ID (PID) tracker follows one or more process IDs; only
the processes with a tracked PID are allowed to emit events. By
default, all possible PIDs on the system are tracked: any process
may emit enabled events (equivalent of lttng track --pid --all for
all domains).
With the PID tracker, it is possible, for example, to record all
system calls called by a given process:
# lttng enable-event --kernel --all --syscall
# lttng track --kernel --pid=2345
# lttng start
If all the PIDs are tracked (i.e. lttng track --pid --all, which
is the default state of all domains when creating a tracing
session), then using the track command with one or more specific
PIDs has the effect of first removing all the PIDs from the
whitelist, then adding the specified PIDs.
Example
Assume the maximum system PID is 7 for this example.
Initial whitelist:
[0] [1] [2] [3] [4] [5] [6] [7]
Command:
$ lttng track --userspace --pid=3,6,7
Whitelist:
[ ] [ ] [ ] [3] [ ] [ ] [6] [7]
Command:
$ lttng untrack --userspace --pid=7
Whitelist:
[ ] [ ] [ ] [3] [ ] [ ] [6] [ ]
Command:
$ lttng track --userspace --pid=1,5
Whitelist:
[ ] [1] [ ] [3] [ ] [5] [6] [ ]
It should be noted that the PID tracker tracks the numeric process
IDs. Should a process with a given ID exit and another process be
given this ID, then the latter would also be allowed to emit
events.
See the lttng-untrack(1) for more details about removing entries.
General options are described in lttng(1).
Domain
One of:
-k, --kernel
Track resources in the Linux kernel domain.
-u, --userspace
Track resources in the user space domain.
Target
-s SESSION, --session=SESSION
Track resources in the tracing session named SESSION instead
of the current tracing session.
Tracking
-a, --all
Used in conjunction with an empty --pid option: track all
process IDs (add all entries to the whitelist).
-p [PID[,PID]...], --pid[=PID[,PID]...]
Track process IDs PID (add them to 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.
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)).
/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.
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 <https://bugs.lttng.org/projects/lttng-
tools>.
• 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: [email protected]
• IRC channel <irc://irc.oftc.net/lttng>: #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 <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.
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.
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]>.
lttng-untrack(1), lttng(1)
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 [email protected]. 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
[email protected]
LTTng 2.12.0-pre 10/29/2018 LTTNG-TRACK(1)
Pages that refer to this page: lttng(1), lttng-enable-event(1), lttng-untrack(1)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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