lttng-untrack — Remove one or more values from an LTTng process attribute tracker
Remove specific process attribute values from a Linux kernel domain tracker:
lttng [GENERAL OPTIONS] untrack--kernel(--pid=PID[,PID]… |--vpid=VPID[,VPID]… |--uid=UID[,UID]… |--vuid=VUID[,VUID]… |--gid=GID[,GID]… |--vgid=VGID[,VGID]… )…
Remove all possible process attribute values from a Linux kernel domain tracker:
lttng [GENERAL OPTIONS] untrack--kernel--all(--pid|--vpid|--uid|--vuid|--gid|--vgid)…
Remove specific process attribute values from a user space domain tracker:
lttng [GENERAL OPTIONS] untrack--userspace(--vpid=VPID[,VPID]… |--vuid=VUID[,VUID]… |--vgid=VGID[,VGID]…)…
Remove all possible process attribute values from a user space domain tracker:
lttng [GENERAL OPTIONS] untrack--userspace--all(--vpid|--vgid|--vuid)…
The lttng untrack commands removes one or more values from a
process attribute tracker.
See lttng-track(1) to learn more about LTTng trackers.
The untrack command removes specific process attribute values from a
tracker’s inclusion set. The attributes to remove must have been
precedently added by lttng-track(1). It is also possible to remove
all the possible values of a process attribute from the inclusion set
using the --all option.
One common operation is to create a tracing session (see lttng-create(1)), remove all the entries from the PID tracker inclusion set, 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 inclusion set:
[0] [1] [2] [3] [4] [5] [6] [7]
Command:
$
lttng untrack --kernel --pid --all
inclusion set:
[ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ]
Commands:
$ $ $ $
lttng enable-event --kernel ... lttng start # ... lttng track --kernel --pid=3,5
inclusion set:
[ ] [ ] [ ] [3] [ ] [5] [ ] [ ]
Command:
$
lttng track --kernel --pid=2
inclusion set:
[ ] [ ] [2] [3] [ ] [5] [ ] [ ]
General options are described in lttng(1).
One of:
-k, --kernel
Track process attributes in the Linux kernel domain.
-u, --userspace
Track process attributes in the user space domain.
-a, --all
Used in conjunction with a single, empty --pid,
--vpid, --uid, --vuid, --gid,
or --vgid option: untrack all possible process attribute
values (remove all values from the inclusion set).
-p [PID[,PID]…], --pid[=PID[,PID]…]
Untrack process ID values PID (remove them from the process ID
inclusion set).
PID is the process ID attribute of a process as seen from the root
PID namespace (see pid_namespaces(7)). It can only be used with
the --kernel domain option.
The PID argument must be omitted when also using the --all
option.
--vpid[=VPID[,VPID]…]
Untrack virtual process ID values VPID (remove them from the
virtual process ID inclusion set).
VPID is the virtual process ID attribute of a process as seen from
the PID namespace of the process (see pid_namespaces(7)).
The VPID argument must be omitted when also using the --all
option.
--uid[=USER[,USER]…]
Untrack user ID process attribute values USER (remove them from
the user ID inclusion set).
USER is the real user ID (see getuid(3)) of a process as seen
from the root user namespace (see user_namespaces(7)). It can
only be used with the --kernel domain option.
USER can also be a user name. No name resolution is performed;
USER will be matched against the names in the inclusion set.
The USER argument must be omitted when also using the --all
option.
--vuid[=USER[,USER]…]
Untrack virtual user ID process attribute values USER (remove
them from the virtual user ID inclusion set).
USER is the real user ID (see getuid(3)) of a process as seen
from the user namespace of the process (see user_namespaces(7)).
USER can also be a user name. No name resolution is performed;
USER will be matched against the names in the inclusion set.
The USER argument must be omitted when also using the --all
option.
--gid[=GROUP[,GROUP]…]
Untrack group ID process attribute values GROUP (remove them
from the group ID inclusion set).
GROUP is the real group ID (see getgid(3)) of a process as seen
from the root user namespace (see user_namespaces(7)). It can
only be used with the --kernel domain option.
GROUP can also be a group name. No name resolution is performed;
GROUP will be matched against the names in the inclusion set.
The GROUP argument must be omitted when also using the --all
option.
--vgid[=GROUP[,GROUP]…]
Untrack virtual group ID process attribute values GROUP(remove
them from the virtual group ID inclusion set).
GROUP is the real group ID (see getgid(3)) of a process as seen
from the user namespace of the process (see user_namespaces(7)).
GROUP can also be a group name. No name resolution is performed;
GROUP will be matched against the names in the inclusion set.
The GROUP 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.
$LTTNG_HOME/.lttng/sessions
Default location of saved user tracing sessions (see lttng-save(1) and lttng-load(1)).
/etc/lttng/sessions
System-wide location of saved tracing sessions (see lttng-save(1) and lttng-load(1)).
Note:$LTTNG_HOME defaults to $HOME when not explicitly set.
Success
Command error
Undefined command
Fatal error
Command warning (something went wrong during the command)
If you encounter any issue or usability problem, please report it on the LTTng bug tracker.
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.