The lttng add-context command adds one or more context fields to a
Channels are created with the lttng-enable-channel(1) command.
When context fields are added to a channel, all the events emitted
within this channel contain the dynamic values of those context
If the --session option is omitted, the current tracing session is
used. If the --channel option is omitted, the context fields are
added to all the selected tracing session’s channels.
Many context fields can be added to a channel at once by repeating
the --type option.
perf counters are available as per-CPU (perf:cpu: prefix) as well as
per-thread (perf:thread: prefix) counters. Currently, per-CPU
counters can only be used in the Linux kernel tracing domain, while
per-thread counters can only be used in the user space tracing
It is also possible to enable PMU counters by raw ID using the
perf:cpu:raw:rN:NAME (Linux kernel tracing domain) or
perf:thread:raw:rN:NAME (user space tracing domain), with:
A hexadecimal event descriptor which is the same format as used
by perf-record(1): a concatenation of the event number and umask
value provided by the processor’s manufacturer. The possible
values for this field are processor-specific.
Custom name to easily recognize the counter.
Application-specific context fields can be added to a channel using
the following syntax:
Context type name.
Make sure to single-quote the type when running the command from
a shell, as $ is a special character for variable substitution in
Use the --list option without other arguments to list the available
context field names.
General options are described in lttng(1).
Add context to channel in the java.util.logging (JUL) domain.
Add context to channel in the Linux kernel domain.
Add context to channel in the Apache log4j domain.
Add context to channel in the user space domain.
Target-c CHANNEL, --channel=CHANNEL
Add context fields to a channel named CHANNEL instead of adding
them to all the channels.
-s SESSION, --session=SESSION
Add context fields to a channel in the tracing session named
SESSION instead of the current tracing session.
List the available context fields. Use this option alone.
-t TYPE, --type=TYPE
Add context field named TYPE. This option can be repeated as many
times as needed on the command-line.
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 firstname.lastname@example.org. 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-ADD-CONTEXT(1)