[lttng-dev] [RELEASE] LTTng-UST 2.5.0-rc1

Mathieu Desnoyers mathieu.desnoyers at efficios.com
Wed May 28 10:39:01 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.

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.

Detailed changelog:
2014-05-28 (International Hamburger Day) lttng-ust 2.5.0-rc1
        * Fix: out of tree build for lib Java and JUL
        * Fix: default loglevel is DEBUG
        * Fix: refuse overwrite mode buffers with less than two subbuffers
        * Fix: tracef.h: add missing c++ guard
        * Fix: remove JUL loglevel filtering from the agent
        * Fix: cleanup JUL agent state on sessiond disconnect
        * Fix: Move generated headers to the BUILT_SOURCES target
        * Fix: perf ust: check close return value
        * Cleanup: work-around missing inet.h struct mmsghdr fwd declaration
        * Implement LTTng-UST perf counters support on x86
        * Fix linking failure when cross-compiling
        * Fix: disable liblttng-ust-dl if dlinfo is not available in C library
        * Fix: pass proper args when writing commit counter
        * Fix: pad strings that are modified concurrently with tracing
        * Fix: Use $AM_CC when it is defined instead of gcc in demo-tracef
        * Revert "Fix: disable liblttng-ust-dl if dlinfo is not available in C library"
        * Fix: .split() the CC environment variable in lttng-gen-tp
        * Fix: disable liblttng-ust-dl if dlinfo is not available in C library
        * Fix: python invocation through env
        * Change default loglevel to TRACE_DEBUG_LINE
        * Fix: Override AM_PATH_PYTHON's default action-if-not-found
        * Fix: don't accept configure --disable-shared
        * Fix: configure.ac: add missing result to alignment req. check
        * Fix: malloc wrapper: infinite recursion with compat TLS
        * Fix: lttng-ust needs -ldl for tracef()
        * Fix: typo in lttng-ust.3
        * Fix: liblttng-ust-libc-wrapper recursive use of calloc
        * Fix: add demo-tracef to dist tarball
        * Fix: add missing header files for tracef
        * Implement tracef() instrumentation API
        * Add 'unused' attribute to tracepoint callback
        * Use autoconf AM_MAINTAINER_MODE
        * Fix: mismatch between code and comments
        * Fix: incorrect urcu git URL in README

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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