lttng-enable-event(1)
=====================
-:revdate: 12 May 2021
+:revdate: 25 May 2021
NAME
Without the option:--channel option::
The channel named `channel0`.
+
-If such a channel doesn't exist, the `enable-event` automatically
-creates it.
+If there's already a channel for the selected tracing session and domain
+which isn't named `channel0`, the `enable-event` command fails.
+Otherwise, it automatically creates it.
+
+See the <<examples,EXAMPLES>> section below for usage examples.
List the recording event rules of a specific tracing session
and/or channel with the man:lttng-list(1) and man:lttng-status(1)
from the most to the least severe:
User space (option:--userspace option)::
- Shortcuts such as `system` are allowed.
-+
-* `TRACE_EMERG` (0)
-* `TRACE_ALERT` (1)
-* `TRACE_CRIT` (2)
-* `TRACE_ERR` (3)
-* `TRACE_WARNING` (4)
-* `TRACE_NOTICE` (5)
-* `TRACE_INFO` (6)
-* `TRACE_DEBUG_SYSTEM` (7)
-* `TRACE_DEBUG_PROGRAM` (8)
-* `TRACE_DEBUG_PROCESS` (9)
-* `TRACE_DEBUG_MODULE` (10)
-* `TRACE_DEBUG_UNIT` (11)
-* `TRACE_DEBUG_FUNCTION` (12)
-* `TRACE_DEBUG_LINE` (13)
-* `TRACE_DEBUG` (14)
++
+* `EMERG` (0)
+* `ALERT` (1)
+* `CRIT` (2)
+* `ERR` (3)
+* `WARNING` (4)
+* `NOTICE` (5)
+* `INFO` (6)
+* `DEBUG_SYSTEM` (7)
+* `DEBUG_PROGRAM` (8)
+* `DEBUG_PROCESS` (9)
+* `DEBUG_MODULE` (10)
+* `DEBUG_UNIT` (11)
+* `DEBUG_FUNCTION` (12)
+* `DEBUG_LINE` (13)
+* `DEBUG` (14)
`java.util.logging` (option:--jul option)::
- Shortcuts such as `severe` are allowed.
-+
-* `JUL_OFF` (`INT32_MAX`)
-* `JUL_SEVERE` (1000)
-* `JUL_WARNING` (900)
-* `JUL_INFO` (800)
-* `JUL_CONFIG` (700)
-* `JUL_FINE` (500)
-* `JUL_FINER` (400)
-* `JUL_FINEST` (300)
-* `JUL_ALL` (`INT32_MIN`)
++
+* `OFF` (`INT32_MAX`)
+* `SEVERE` (1000)
+* `WARNING` (900)
+* `INFO` (800)
+* `CONFIG` (700)
+* `FINE` (500)
+* `FINER` (400)
+* `FINEST` (300)
+* `ALL` (`INT32_MIN`)
Apache log4j (option:--log4j option)::
- Shortcuts such as `severe` are allowed.
+
-* `LOG4J_OFF` (`INT32_MAX`)
-* `LOG4J_FATAL` (50000)
-* `LOG4J_ERROR` (40000)
-* `LOG4J_WARN` (30000)
-* `LOG4J_INFO` (20000)
-* `LOG4J_DEBUG` (10000)
-* `LOG4J_TRACE` (5000)
-* `LOG4J_ALL` (`INT32_MIN`)
+* `OFF` (`INT32_MAX`)
+* `FATAL` (50000)
+* `ERROR` (40000)
+* `WARN` (30000)
+* `INFO` (20000)
+* `DEBUG` (10000)
+* `TRACE` (5000)
+* `ALL` (`INT32_MIN`)
Python (option:--python option)::
- Shortcuts such as `critical` are allowed.
+
-* `PYTHON_CRITICAL` (50)
-* `PYTHON_ERROR` (40)
-* `PYTHON_WARNING` (30)
-* `PYTHON_INFO` (20)
-* `PYTHON_DEBUG` (10)
-* `PYTHON_NOTSET` (0)
+* `CRITICAL` (50)
+* `ERROR` (40)
+* `WARNING` (30)
+* `INFO` (20)
+* `DEBUG` (10)
+* `NOTSET` (0)
[[filter-cond]]
include::common-lttng-cmd-after-options.txt[]
+[[examples]]
+EXAMPLES
+--------
+.Create a recording event rule which matches all Linux system call events (current tracing session, default channel).
+====
+See the option:--all and option:--syscall options.
+
+[role="term"]
+----
+$ lttng enable-event --kernel --all --syscall
+----
+====
+
+.Create a recording event rule which matches user space tracepoint events named specifically (current tracing session, default channel).
+====
+The recording event rule below matches all user space tracepoint events
+of which the name starts with `my_provider:msg`.
+
+[role="term"]
+----
+$ lttng enable-event --userspace 'my_provider:msg*'
+----
+====
+
+.Create three recording event rules which match Python logging events named specifically (current tracing session, default channel).
+====
+[role="term"]
+----
+$ lttng enable-event --python server3,ui.window,user-mgmt
+----
+====
+
+.Create a recording event rule which matches Apache log4j logging events with a specific log level range (current tracing session, specific channel).
+====
+See the option:--channel, option:--all, and option:--loglevel options.
+
+[role="term"]
+----
+$ lttng enable-event --log4j --channel=my-loggers \
+ --all --loglevel=INFO
+----
+====
+
+.Create a recording event rule which matches specific Linux kprobe events (current tracing session, default channel).
+====
+The recording event rule below matches the entry of `usb_disconnect()`
+Linux kernel function calls. The records of such events are named `usbd`
+(see the <<er-name,Event record name>> section above).
+
+See the option:--probe option.
+
+[role="term"]
+----
+$ lttng enable-event --kernel --probe=usb_disconnect usbd
+----
+====
+
+.Create a recording event rule which matches Linux kernel tracepoint events which satisfy an event payload and context filter (specific tracing session, default channel).
+====
+See the option:--session and option:--filter options.
+
+[role="term"]
+----
+$ lttng enable-event --kernel --session=my-session 'sched_*' \
+ --filter='$ctx.preemptible && comm != "systemd*"'
+----
+====
+
+.Enable two Linux kernel tracepoint recording event rules (current tracing session, specific channel).
+====
+See the option:--channel option.
+
+[role="term"]
+----
+$ lttng enable-event --kernel --channel=tva ja,wendy
+----
+====
+
+
include::common-footer.txt[]
projects / lttng-tools.git / blobdiff