Document kernel events filtering

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>

diff --git a/contents/understanding-lttng/core-concepts/domain.md b/contents/understanding-lttng/core-concepts/domain.md
index b0cb5281cbe58a9e7aced9d35a3ca09d4eeb0004..e0631eacb7d69129bb0899b1c9775b7cc6bb2aab 100644 (file)
--- a/contents/understanding-lttng/core-concepts/domain.md
+++ b/contents/understanding-lttng/core-concepts/domain.md
@@ -20,7 +20,6 @@ source code), you need to specify which one is concerned when enabling
 an event because both domains could have existing events with the same
 name.
 
 an event because both domains could have existing events with the same
 name.
 

-Some features are not available in all domains. Filtering enabled
-events using custom expressions, for example, is currently not
-supported in the kernel domain, but support could be added in the
-future.
+Some features are reserved for some domains. Dynamic function entry/return
+instrumentation, for example, is currently only supported in the kernel
+domain, but support for other domains could be added in the future.

diff --git a/contents/using-lttng/controlling-tracing/enabling-disabling-events.md b/contents/using-lttng/controlling-tracing/enabling-disabling-events.md
index 26ab44eafbbbdd9ae61681c3597ccf5b9a61433e..5c40f4cbbcc4787a6cde6fdfa1dce5cf84fc732e 100644 (file)
--- a/contents/using-lttng/controlling-tracing/enabling-disabling-events.md
+++ b/contents/using-lttng/controlling-tracing/enabling-disabling-events.md
@@ -16,13 +16,13 @@ composed of:
      (required).
   2. One or many **instrumentation points** in source code or binary
      program (tracepoint name, address, symbol name, function name,
      (required).
   2. One or many **instrumentation points** in source code or binary
      program (tracepoint name, address, symbol name, function name,

-     logger name, amongst other types of probes) to be executed (required).
+     logger name, amongst other types of probes) to be executed
+     (required).

   3. A **log level** (each instrumentation point declares its own log
      level) or log level range to match (optional; only valid for user
      space domain).
   4. A **custom user expression**, or **filter**, that must evaluate to
   3. A **log level** (each instrumentation point declares its own log
      level) or log level range to match (optional; only valid for user
      space domain).
   4. A **custom user expression**, or **filter**, that must evaluate to

-     _true_ when a tracepoint is executed (optional; only valid for user
-     space domain).
+     _true_ when a tracepoint is executed (optional).

 
 All conditions are specified using arguments passed to the
 `enable-event` command of the `lttng` tool.
 
 All conditions are specified using arguments passed to the
 `enable-event` command of the `lttng` tool.


@@ -80,6 +80,8 @@ lttng enable-event -k --tracepoint sched_switch
 lttng enable-event -k --tracepoint gpio_value
 lttng enable-event -k --function usb_probe_device usb_probe_device
 lttng enable-event -k --syscall --all
 lttng enable-event -k --tracepoint gpio_value
 lttng enable-event -k --function usb_probe_device usb_probe_device
 lttng enable-event -k --syscall --all

+lttng enable-event -k --tracepoint irq_handler_entry  \
+                   --filter 'irq == 28 || irq == 17'

 </pre>
 
 The wildcard symbol, `*`, matches _anything_ and may only be used at
 </pre>
 
 The wildcard symbol, `*`, matches _anything_ and may only be used at


@@ -89,8 +91,8 @@ undesired shell expansion.
 
 System call events can be enabled individually, too:
 
 
 System call events can be enabled individually, too:
 

-<pre class="term">
-lttng enable-event -k --syscall open
+<pre class="term" style="position: relative">
+<div class="since">Since 2.6</div>lttng enable-event -k --syscall open

 lttng enable-event -k --syscall read
 lttng enable-event -k --syscall fork,chdir,pipe
 </pre>
 lttng enable-event -k --syscall read
 lttng enable-event -k --syscall fork,chdir,pipe
 </pre>