- 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".
needed.
- 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.
- 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.