X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=README;h=78160a30f8210e0cdb9e8e6e8483aa3a6204e117;hb=69b8d2fae1590ec792409587123afa55b8959c07;hp=b3f4c5b29de5362d478b6abbcfbb94a483894573;hpb=1bb74e9451525065d72a7647190eb355aa7ccd85;p=lttng-ust.git diff --git a/README b/README index b3f4c5b2..78160a30 100644 --- a/README +++ b/README @@ -56,22 +56,45 @@ USAGE: - Create an instrumentation header following the tracepoint examples. See lttng/tracepoint.h, and examples. - - Either compile the Tracepoint probes with the application: + + 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 + "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 -llttng-ust". + - 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 "-lllttng-ust". + - 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 - - Or compile the Tracepoint probes separately from the application, - using dynamic linking: + + 2) Compile the Tracepoint Provider separately from the application, + using dynamic linking: + - Into exactly one object of your application: define + "TRACEPOINT_DEFINE" _and_ also define + "TRACEPOINT_PROBE_DYNAMIC_LINKAGE", then include the tracepoint + provider header. + - Include the tracepoint provider header into all instrumented C + files that use the provider. - Compile the tracepoint provider with "-I.". - Link the tracepoint provider with "-llttng-ust". - 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 + - Enable instrumentation and control tracing with the "lttng" command from lttng-tools. See lttng-tools doc/quickstart.txt. @@ -90,6 +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: @@ -117,7 +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.