Kernel Tracing
--------------
-You have to modprobe the lttng-modules manually or the session daemon will do
-it for you if those modules can be found on your system.
+You can start the session daemon by invoking the command "ltt-sessiond",
+or let the lttng command line tool do it for you. The session daemon
+loads the LTTng tracer modules for you if those modules can be found on
+your system. If they are not found, the kernel tracing feature will be
+unavailable.
-Again, you can then start the session daemon (ltt-sessiond) by hand or the
-lttng command line tool will do it for you.
-
-List possible kernel events:
+List available kernel events:
# lttng list -k
enable a dynamic probe and data will be output in the trace along side with
your tracing data.
-# lttng enable-event aname --probe symbol+0xffff7260695
+# lttng enable-event aname -k --probe symbol+0xffff7260695
or
-# lttng enable-event aname --probe 0xffff7260695
+# lttng enable-event aname -k --probe 0xffff7260695
Either an <address> or a <symbol+offset> can be used for probes.
You can also enable function tracer, which uses the Ftrace API (by Steven
Rostedt). Again, data will be output in the trace.
-# lttng enable-event aname --function <symbol_name>
+# lttng enable-event aname -k --function <symbol_name>
4) Enable context information for an event:
Reading a trace
--------------
-To read your trace, you can use babeltrace which will text dump your the
-trace. Please see http://www.efficios.com/ctf and git tree
+The tool "Babeltrace" can be used to dump your binary trace into a
+human-readable text format. Please see
+http://www.efficios.com/babeltrace and git tree
http://git.efficios.com/?p=babeltrace.git
# babeltrace -n $HOME/lttng-traces/mysession-<date>-<time> | less