Update manpage about LTTNG_UST_DEBUG effect

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

diff --git a/doc/man/lttng-ust.3 b/doc/man/lttng-ust.3
index 2c58fba19197cbfe1fc89d86f3f328b1c6cf3f69..6f8763b9d2dcaa2f9b19cb12358de256f1d49dcd 100644 (file)
--- a/doc/man/lttng-ust.3
+++ b/doc/man/lttng-ust.3
@@ -17,7 +17,38 @@ port of the low-overhead tracing capabilities of the LTTng kernel tracer
 to user-space. The library "liblttng-ust" enables tracing of
 applications and libraries.
 
-.SH "USAGE"
+.SH "USAGE WITH TRACEF"
+.PP
+The simplest way to add instrumentation to your code is by far the
+tracef() API. To do it, in a nutshell:
+
+1) #include <lttng/tracef.h>
+
+2) /* in your code, use like a printf */
+   tracef("my message, this 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 -a
+   lttng start
+   [... run your program ...]
+   lttng stop
+   lttng view
+
+That's it!
+
+If you want to have more flexibility and control on the event names,
+payload typing, etc, you can continue reading on and use the tracepoints
+below. "tracef()" is there for quick and dirty ad hoc instrumentation,
+whereas tracepoint.h is meant for thorough instrumentation of a code
+base to be integrated with an upstream project.
+.PP
+
+.SH "USAGE WITH TRACEPOINT"
 .PP
 The simple way to generate the lttng-ust tracepoint probes is to use the
 lttng-gen-tp(1) tool. See the lttng-gen-tp(1) manpage for explanation.
@@ -61,11 +92,11 @@ TRACEPOINT_EVENT(
        sample_component,
 
        /*
-        * tracepoint name, same format as sample provider. Does not
-        * need to be declared before. in this case the name is
-        * "message"
+        * tracepoint name, characters permitted follow the same
+        * constraints as the provider name. The name of this example
+        * event is "sample_event".
         */
-       message,
+       sample_event,
 
        /*
         * TP_ARGS macro contains the arguments passed for the tracepoint
@@ -234,7 +265,7 @@ debug information.
    debug information with line-level scope (TRACEPOINT_EVENT default)
 
    TRACE_DEBUG           14
-   debug-level message (trace_printf default)
+   debug-level message
 
 See lttng(1) for information on how to use LTTng-UST loglevels.
 
@@ -268,17 +299,13 @@ There are 2 ways to compile the Tracepoint Provider with the
 application: either statically or dynamically. Please follow
 carefully:
 
-  1.1) Compile the Tracepoint provider with the application, either
-       directly or through a static library (.a):
-    - Into exactly one object of your application: define
+  1) Compile the Tracepoint Provider with the application, either
+     directly or through a static library (.a):
+    - Into exactly one object of your application, define
       "TRACEPOINT_DEFINE" and include the tracepoint provider.
     - Use "\-I." for the compilation unit containing the tracepoint
-      provider include (e.g. tp.c).
-    - Link application with "\-ldl".
-    - If building the provider directly into the application,
-      link the application with "\-llttng-ust".
-    - If building a static library for the provider, link the static
-      library with "\-llttng-ust".
+      provider include (e.g., tp.c).
+    - Link the application with "\-llttng-ust" and "\-ldl".
     - Include the tracepoint provider header into all C files using
       the provider.
     - Examples:
@@ -366,13 +393,9 @@ Pthread identifier. Can be used on architectures where pthread_t maps
 nicely to an unsigned long type.
 .PP
 
-.SH "BASE ADDRESS STATEDUMP (Experimental feature)"
+.SH "BASE ADDRESS STATEDUMP"
 
 .PP
-Warning: This is an experimental feature known to cause deadlocks when the
-traced application uses fork, clone or daemon. Only use it for debugging and
-testing.  Do NOT use it in production.
-
 If an application that uses liblttng-ust.so becomes part of a session,
 information about its currently loaded shared objects will be traced to the
 session at session-enable time. To record this information, the following event
@@ -397,7 +420,7 @@ line number lookup are traced by LTTng.
 
 .PP
 .IP "LTTNG_UST_DEBUG"
-Activate liblttng-ust debug output.
+Activate liblttng-ust debug and error output.
 .PP
 .IP "LTTNG_UST_REGISTER_TIMEOUT"
 The environment variable "LTTNG_UST_REGISTER_TIMEOUT" can be used to
@@ -409,8 +432,8 @@ specified in milliseconds. The value 0 means "don't wait". The value
 recommended for applications with time constraints on the process
 startup time.
 .PP
-.IP "LTTNG_UST_WITH_EXPERIMENTAL_BADDR_STATEDUMP"
-Experimentally allow liblttng-ust to perform a base-address statedump on session-enable.
+.IP "LTTNG_UST_WITHOUT_BADDR_STATEDUMP"
+Prevent liblttng-ust to perform a base-address statedump on session-enable.
 .PP
 
 .SH "SEE ALSO"