Doc: add LTTNG_UST_GETCPU_PLUGIN to man page

[lttng-ust.git] / doc / man / lttng-ust.3

diff --git a/doc/man/lttng-ust.3 b/doc/man/lttng-ust.3
index 7dae8b538d8d4161e57f54bee9e5a872815e6f02..4d86bfe0268076f05e1bfffb6f913a6156bc7106 100644 (file)
--- a/doc/man/lttng-ust.3
+++ b/doc/man/lttng-ust.3
@@ -48,6 +48,41 @@ whereas tracepoint.h is meant for thorough instrumentation of a code
 base to be integrated with an upstream project.
 .PP
 
+.SH "USAGE WITH TRACELOG"
+.PP
+If you want to migrate existing logging (info, errors, ...)
+to LTTng UST, you can use the tracelog() interface.
+To do it, in a nutshell:
+
+1) #include <lttng/tracelog.h>
+
+2) /* in your code, use like a printf, with extra loglevel info. */
+   tracelog(TRACE_INFO, "Message with integer %d", 1234);
+
+3) Link your program against liblttng-ust.so.
+
+4) Enable UST events when tracing with the following sequence of commands
+   from lttng-tools:
+
+   lttng create
+   lttng enable-event -u "lttng_ust_tracelog:*"
+   lttng start
+   [... run your program ...]
+   lttng stop
+   lttng view
+
+That's it!
+
+You can replace the enable-event line above with a selection of
+loglevels, e.g.:
+
+   lttng enable-event -u -a --loglevel TRACE_INFO
+
+Which will gather all events from TRACE_INFO and more important
+loglevels.
+
+.PP
+
 .SH "USAGE WITH TRACEPOINT"
 .PP
 The simple way to generate the lttng-ust tracepoint probes is to use the
@@ -462,6 +497,12 @@ startup time.
 .IP "LTTNG_UST_WITHOUT_BADDR_STATEDUMP"
 Prevent liblttng-ust to perform a base-address statedump on session-enable.
 .PP
+.IP "LTTNG_UST_GETCPU_PLUGIN"
+Used by the getcpu override plugin system. The environment variable
+provides the path to the shared object which will act as the getcpu override
+plugin. An example can be found in the lttng-ust documentation under
+examples/getcpu-override .
+.PP
 
 .SH "SEE ALSO"