lttng-add-context(1)
====================
-:revdate: 3 May 2021
+:revdate: 6 May 2021
NAME
Without the option:--list option::
Add one or more context fields to be recorded by LTTng to the event
- records of a given channel, or of all the channels of:
+ records of:
+
With the option:--session='SESSION' option:::
The tracing session named 'SESSION'.
The current tracing session (see man:lttng-concepts(7) to learn more
about the current tracing session).
+With the option:--channel='CHANNEL':::
+ The channel named 'CHANNEL'.
+
+Without the option:--channel option:::
+ *All* the channels of the selected tracing session.
+
With the option:--list option::
List the available context field types.
See man:lttng-concepts(7) to learn more about tracing sessions and
channels.
-Without the option:--channel option, LTTng adds context fields to be
-recorded to the event records of *all* the channels of the selected
-tracing session.
-
Repeat the option:--type='TYPE' option to add more than one context
field to be recorded. 'TYPE' is one of:
* An LTTng application-specific context field name:
+
+--
[verse]
$app.'PROVIDER':__TYPE__
+
'TYPE'::
Context type name.
+--
++
+Only available with the option:--jul and option:--log4j options.
IMPORTANT: Make sure to **single-quote** 'TYPE' when you run the
`add-context` command from a shell, as `$` is a special character for
to be recorded to the event records of a given channel once its tracing
session has been started (see man:lttng-start(1)) at least once.
+See the <<examples,EXAMPLES>> section below for usage examples.
-include::common-cmd-options-head.txt[]
+
+include::common-lttng-cmd-options-head.txt[]
Tracing domain
Repeat this option to add more than one context field.
-include::common-cmd-help-options.txt[]
+include::common-lttng-cmd-help-options.txt[]
+
+
+include::common-lttng-cmd-after-options.txt[]
+
+
+[[examples]]
+EXAMPLES
+--------
+.List the available context field types.
+====
+See the option:--list option.
+
+[role="term"]
+----
+$ lttng add-context --list
+----
+====
+
+.Add a single statically-known context field to be recorded to all the Linux kernel channels of the current tracing session.
+====
+[role="term"]
+----
+$ lttng add-context --kernel --type=pid
+----
+====
+
+.Add three statically-known context fields to be recorded to a specific user space channel of a specific tracing session.
+====
+See the option:--session and option:--channel options.
+
+[role="term"]
+----
+$ lttng add-context --userspace --session=my-session \
+ --channel=my-channel \
+ --type=vpid --type=procname --type=ip
+----
+====
+
+.Add a perf counter context field to be recorded to a specific Linux kernel channel of the current tracing session.
+====
+See the option:--channel option.
+
+[role="term"]
+----
+$ lttng add-context --kernel --channel=my-channel \
+ --type=perf:cpu:cache-misses
+----
+====
+
+.Add an LTTng application-specific context field to be recorded to all the JUL channels of the current tracing session.
+====
+[role="term"]
+----
+$ lttng add-context --jul --type='$app.my_server:user_cnt'
+----
+====
-include::common-cmd-footer.txt[]
+include::common-footer.txt[]
SEE ALSO
--------
man:lttng(1),
-man:lttng-concepts(7),
-man:lttng-enable-channel(1)
+man:lttng-enable-channel(1),
+man:lttng-concepts(7)