X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=README;h=78160a30f8210e0cdb9e8e6e8483aa3a6204e117;hb=9d36f30e825135d8fbb3ba6cb31ab10aa938b135;hp=45521d00c6fe5c8b615aadec45021b33d6a5f83e;hpb=0ba9b647b1db5d3e3f4196941401e01f255d9175;p=lttng-ust.git diff --git a/README b/README index 45521d00..78160a30 100644 --- a/README +++ b/README @@ -90,15 +90,11 @@ USAGE: - 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: @@ -144,7 +144,7 @@ PACKAGE CONTENTS: - tests Various test programs - - liblttng-ust-libc + - liblttng-ust-libc-wrapper An example library that can be LD_PRELOAD'ed to instrument some calls to libc (currently malloc() and free()) in any program without need to recompile it.