X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=contents%2Fusing-lttng%2Fcontrolling-tracing%2Fenabling-disabling-events.md;h=5c40f4cbbcc4787a6cde6fdfa1dce5cf84fc732e;hb=1bf7ee862bb9826b5b48a432af54477ae5e04ff7;hp=5701543197730d05faeaccace3b9626e9d222607;hpb=f11aa623d30b8d6b3b6a2b8d677c491474ecb018;p=lttng-docs.git diff --git a/contents/using-lttng/controlling-tracing/enabling-disabling-events.md b/contents/using-lttng/controlling-tracing/enabling-disabling-events.md index 5701543..5c40f4c 100644 --- 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, - logger name, etc.) 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 - _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. @@ -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 irq_handler_entry \ + --filter 'irq == 28 || irq == 17' 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: -
-lttng enable-event -k --syscall open
+
+
Since 2.6
lttng enable-event -k --syscall open lttng enable-event -k --syscall read lttng enable-event -k --syscall fork,chdir,pipe
@@ -139,7 +141,7 @@ Disabling an event does not add it to some blacklist: it simply removes it from its channel's whitelist. This is why you cannot disable an event which wasn't previously enabled. -A disabled event will not generate any trace data, even if all its +A disabled event doesn't generate any trace data, even if all its specified conditions are met. Events may be enabled and disabled at will, either when LTTng tracers