lttng-enable-channel(1)
=======================
-:revdate: 3 May 2021
+:revdate: 14 June 2021
NAME
The channel(s) to create or enable belong to:
With the option:--session='SESSION' option::
- The tracing session named 'SESSION'.
+ The recording session named 'SESSION'.
Without the option:--session option::
- The current tracing session (see man:lttng-concepts(7) to learn more
- about the current tracing session).
+ The current recording session (see man:lttng-concepts(7) to learn
+ more about the current recording session).
NOTE: The man:lttng-enable-event(1) command can automatically create a
default channel when no channel exists for the provided tracing domain.
-List the channels of a given tracing session with the
+See the ``<<examples,EXAMPLES>>'' section below for usage examples.
+
+List the channels of a given recording session with the
man:lttng-list(1) and man:lttng-status(1) commands.
Disable an enabled channel with the man:lttng-disable-channel(1)
* Change an attribute of an existing channel.
-* Enable a disabled channel once its tracing session has been active
+* Enable a disabled channel once its recording session has been active
(started; see man:lttng-start(1)) at least once.
-* Create a channel once its tracing session has been active at least
+* Create a channel once its recording session has been active at least
once.
* Create a user space channel with a given buffering scheme
(option:--buffers-uid or option:--buffers-pid options) and create a
second user space channel with a different buffering scheme in the
- same tracing session.
+ same recording session.
====
-include::common-cmd-options-head.txt[]
+include::common-lttng-cmd-options-head.txt[]
Tracing domain
Recording target
~~~~~~~~~~~~~~~~
option:-s 'SESSION', option:--session='SESSION'::
- Create or enable channels in the tracing session named 'SESSION'
- instead of the current tracing session.
+ Create or enable channels in the recording session named 'SESSION'
+ instead of the current recording session.
Buffering scheme
+{default_metadata_switch_timer}+
-include::common-cmd-help-options.txt[]
+include::common-lttng-cmd-help-options.txt[]
+
+
+include::common-lttng-cmd-after-options.txt[]
+
+
+[[examples]]
+EXAMPLES
+--------
+.Create a Linux kernel channel with default attributes in the current recording session.
+====
+The following command line only creates a new channel if `my-channel`
+doesn't name an existing Linux kernel channel in the current recording
+session.
+
+[role="term"]
+----
+$ lttng enable-channel --kernel my-channel
+----
+====
+
+.Create a user space channel with a per-process buffering scheme in a specific recording session.
+====
+See the option:--session and option:--buffers-pid options.
+
+[role="term"]
+----
+$ lttng enable-channel --session=my-session --userspace \
+ --buffers-pid my-channel
+----
+====
+
+.Create a Linux kernel channel in the current recording session with four 32-MiB sub-buffers per ring buffer.
+====
+See the option:--num-subbuf and option:--subbuf-size options.
+
+[role="term"]
+----
+$ lttng enable-channel --kernel my-channel \
+ --num-subbuf=4 --subbuf-size=32M
+----
+====
+
+.Create a user space channel in the current recording session with trace file rotation.
+====
+See the option:--tracefile-count and option:--tracefile-size options.
+
+[role="term"]
+----
+$ lttng enable-channel --userspace my-channel \
+ --tracefile-count=16 --tracefile-size=8M
+----
+====
+
+.Enable two user space channels of a specific recording session.
+====
+[role="term"]
+----
+$ lttng enable-channel --session=my-session --userspace \
+ canal-d,rds
+----
+====
-include::common-cmd-footer.txt[]
+include::common-footer.txt[]
SEE ALSO