counters can only be used in the user space tracing domain.
It is also possible to enable PMU counters by raw ID using the
-`perf:cpu:raw:r<N>:<name>` or `perf:thread:raw:r<N>:<name>` format for
-the kernel and user-space respectively. `<N>` is a hexadecimal event
-descriptor which is the same format as used by perf-record(1): a
-concatenation of the `Umask value` and `Event number` provided by the
-processor's manufacturer. The possible values for this field are
-processor-specific. The `<name>` field is used to associate a clearer
-name to the counter.
+`perf:cpu:raw:rN:NAME` (Linux kernel tracing domain) or
+`perf:thread:raw:rN:NAME` (user space tracing domain), with:
+
+`N`::
+ A hexadecimal event descriptor which is the same format as used
+ by man: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.
+
+`NAME`::
+ Custom name to easily recognize the counter.
Application-specific context fields can be added to a channel using the
following syntax:
Use the option:--list option without other arguments to list the
available context field names.
+See the <<limitations,LIMITATIONS>> section below for a list of
+limitations to consider.
include::common-cmd-options-head.txt[]
Target
~~~~~~
-option:-c, option:--channel='CHANNEL'::
+option:-c 'CHANNEL', option:--channel='CHANNEL'::
Add context fields to a channel named 'CHANNEL' instead of adding
them to all the channels.
-option:-s, option:--session='SESSION'::
+option:-s 'SESSION', option:--session='SESSION'::
Add context fields to a channel in the tracing session named 'SESSION'
instead of the current tracing session.
option:--list::
List the available context fields. Use this option alone.
-option:-t, option:--type='TYPE'::
+option:-t 'TYPE', option:--type='TYPE'::
Add context field named 'TYPE'. This option can be repeated as
many times as needed on the command-line.
include::common-cmd-help-options.txt[]
+[[limitations]]
+LIMITATIONS
+-----------
+As of this version of LTTng, it is not possible to add context fields to
+a channel once its tracing session has been started (see man:lttng-start(1))
+at least once.
include::common-cmd-footer.txt[]