Add man page for lttng-ust-cyg-profile

[lttng-ust.git] / README

diff --git a/README b/README
index 8193c6603837940ffc2cade120ef4dc867b638fe..84cc69133953e8fd9e85ebc81e2dd3c8a443a6c4 100644 (file)
--- a/README
+++ b/README
@@ -16,7 +16,7 @@ PREREQUISITES:
   - liburcu
     Userspace RCU library, by Mathieu Desnoyers and Paul E. McKenney
 
-    -> This release depends on liburcu v0.6.6
+    -> This release depends on liburcu v0.7.2
 
       * Debian/Ubuntu package: liburcu-dev
       * Website:  http://lttng.org/urcu
@@ -34,6 +34,8 @@ compile the git repository tree :
   (make sure your system wide "automake" points to a recent version!)
 - GNU Libtool >=2.2
   (for more information, go to http://www.gnu.org/software/autoconf/)
+- Perl (optional)
+  Needed for make check and tests.
 
 If you get the tree from the repository, you will need to use the "bootstrap"
 script in the root of the tree. It calls all the GNU tools needed to prepare the
@@ -75,7 +77,7 @@ USAGE:
     - Include the tracepoint provider header into all C files using
       the provider.
     - Example:
-        tests/hello/  hello.c tp.c ust_tests_hello.h Makefile.example.*
+      - tests/hello/  hello.c tp.c ust_tests_hello.h Makefile.example.*
 
   2) Compile the Tracepoint Provider separately from the application,
      using dynamic linking:
@@ -97,6 +99,10 @@ USAGE:
 
   - Enable instrumentation and control tracing with the "lttng" command
     from lttng-tools. See lttng-tools doc/quickstart.txt.
+  - Note about dlclose() usage: it is not safe to use dlclose on a
+    provider shared object that is being actively used for tracing due
+    to a lack of reference counting from lttng-ust to the used shared
+    object.
 
 ENVIRONMENT VARIABLES:
 
@@ -113,6 +119,10 @@ ENVIRONMENT VARIABLES:
     recommended for applications with time constraints on the process
     startup time.
 
+  - The compilation flag "-DLTTNG_UST_DEBUG_VALGRIND" should be enabled
+    at build time to allow liblttng-ust to be used with valgrind
+    (side-effect: disables per-cpu buffering).
+
 
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