X-Git-Url: http://git.lttng.org/?p=lttng-ust.git;a=blobdiff_plain;f=README;h=78160a30f8210e0cdb9e8e6e8483aa3a6204e117;hp=78ed56f68067bbdefef3bfb771110eb439377590;hb=abcabd6a23a42744beb0a80afee4104b690f23aa;hpb=90cefaa31af0a85593a155fba8570e04c653225a diff --git a/README b/README index 78ed56f6..78160a30 100644 --- a/README +++ b/README @@ -67,7 +67,7 @@ USAGE: "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" on Linux, with "-lc" on BSD. + - 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 @@ -75,7 +75,7 @@ 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: @@ -87,18 +87,14 @@ USAGE: files that use the provider. - Compile the tracepoint provider with "-I.". - Link the tracepoint provider with "-llttng-ust". - - Link application with "-ldl" on Linux, "-lc" on BSD. + - Link application with "-ldl". - Set a LD_PRELOAD environment to preload the tracepoint provider shared object before starting the application when tracing is - needed. + needed. Another way is to dlopen the tracepoint probe when needed + by the application. - Example: - tests/demo/ demo.c tp*.c ust_tests_demo*.h demo-trace - - Note about dlopen() usage: due to locking side-effects due to the - way libc lazily resolves Thread-Local Storage (TLS) symbols when a - library is dlopen'd, linking the tracepoint probe or liblttng-ust - with dlopen() is discouraged. They should be linked with the - application using "-llibname" or loaded with LD_PRELOAD. - Enable instrumentation and control tracing with the "lttng" command from lttng-tools. See lttng-tools doc/quickstart.txt. @@ -117,6 +113,10 @@ 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). + TRACE VIEWER: