The lttng track commands adds one or more entries to a resource
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
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
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
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.
Assume the maximum system PID is 7 for this example.
       
lttng track --userspace --pid=3,6,7
[ ] [ ] [ ]  [ ] [ ]  
lttng untrack --userspace --pid=7
[ ] [ ] [ ]  [ ] [ ]  [ ]
lttng track --userspace --pid=1,5
[ ]  [ ]  [ ]   [ ]
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).
Track resources in the Linux kernel domain.
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.
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
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 available command options.
Set to 1 to abort the process after the first error is
Overrides the $HOME environment variable. Useful when the user
running the commands has a non-writable home directory.
Absolute path to the man pager to use for viewing help
information about LTTng commands (using lttng-help(1) or lttngCOMMAND --help).
Path in which the session.xsd session configuration XML schema
may be found.
Full session daemon binary path.
The --sessiond-path option has precedence over this environment
Note that the lttng-create(1) command can spawn an LTTng session
daemon automatically if none is running. See lttng-sessiond(8) for
the environment variables influencing the execution of the session
User LTTng runtime configuration.
This is where the per-user current tracing session is stored
between executions of lttng(1). The current tracing session can
be set with lttng-set-session(1). See lttng-create(1) for more
information about tracing sessions.
Default output directory of LTTng traces. This can be overridden
with the --output option of the lttng-create(1) command.
User LTTng runtime and configuration directory.
Default location of saved user tracing sessions (see
lttng-save(1) and lttng-load(1)).
System-wide location of saved tracing sessions (see lttng-save(1)
Note$LTTNG_HOME defaults to $HOME when not explicitly set.
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
LTTng-tools is currently maintained by Jérémie Galarneau
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@example.com. This page was obtained
from the project's upstream Git repository
⟨git://git.lttng.org/lttng-tools.git⟩ on 2017-03-13. 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
LTTng 2.10.0-pre 03/13/2017 LTTNG-TRACK(1)