[lttng-dev] [RELEASE] LTTng-UST 2.5.0

Mathieu Desnoyers mathieu.desnoyers at efficios.com
Wed Jul 16 18:28:31 EDT 2014

LTTng-UST, the Linux Trace Toolkit Next Generation Userspace Tracer, is
port of the low-overhead tracing capabilities of the LTTng kernel tracer
to user-space. The library "liblttng-ust" enables tracing of
applications and libraries.

Noteworthy new features in LTTng-UST 2.5.0:

New and noteworthy:

- New tracef() instrumentation facility. Excerpt from lttng-ust(3) man page:


       The simplest way to add instrumentation to your  code  is  by  far  the
       tracef() API. To do it, in a nutshell:

       1) #include <lttng/tracef.h>

       2) /* in your code, use like a printf */
          tracef("my message, this integer %d", 1234);

       3) Link your program against liblttng-ust.so.

       4) Enable  UST events when tracing with the following sequence of commands
          from lttng-tools:

          lttng create
          lttng enable-event -u -a
          lttng start
          [... run your program ...]
          lttng stop
          lttng view

       That's it!

       If you want to have more flexibility and control on  the  event  names,
       payload  typing,  etc,  you  can continue reading on and use the trace‐
       points below. "tracef()" is there for quick and dirty ad hoc instrumen‐
       tation, whereas tracepoint.h is meant for thorough instrumentation of a
       code base to be integrated with an upstream project.

- Perf PMU counters support from user-space on x86.

- Library base address dump is now stable (thanks to Mentor for their


2014-07-16 (Take Your Poet to Work Day) lttng-ust 2.5.0
        * Mutex while updating statedump_pending is not needed
        * Revert "Turn base address dump into experimental feature"
        * Fix: document ust_fork_mutex nesting
        * Bugfix for #745 deadlock with baddr statedump+fork
        * Move enablers syncing after the channel registration
        * Add lttng_ust_notrace to static inline functions
        * lttng ust: support ppc64le within configure

Project website: http://lttng.org
Download link: http://lttng.org/download
(please refer to the README file for installation instructions)

Mathieu Desnoyers
EfficiOS Inc.

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