[lttng-dev] [RELEASE] LTTng-UST 2.10.0-rc2, 2.9.1, 2.8.3 (Linux user-space tracer)

[Mathieu Desnoyers]

LTTng-UST, the Linux Trace Toolkit Next Generation Userspace Tracer,
is a low-overhead application tracer. The library "liblttng-ust" enables
tracing of applications and libraries.

The 2.10.0-rc2 release contains an important change to the newly
introduced "blocking UST ring buffer" interface:

    Introduce the LTTNG_UST_ALLOW_BLOCKING env. var. to control whether
    applications are allowed to block when a buffer is full. If set, it
    allows the tracer to block the application when buffers are full.
    
    The blocking is now controlled by a per-channel configuration option in
    the LTTng control interface for channels with the "--blocking-timeout"
    parameter, which is specified in usec (or -1 to block forever).
    
    This replaces the LTTNG_UST_BLOCKING_RETRY_TIMEOUT env. var., which
    actually never made it into a stable release (we therefore remove this
    env. var).

This will allow a much more fine-grained control over which channel
end up having a blocking behavior, allowing, for instance, to only
send part of the application events to a blocking buffer, and other
events to a buffer that discards events when full. This change is
introduced in locked-step in lttng-tools 2.10.0-rc2 (which is
expected to be released on June 13). This new environment variable
is described in the lttng-ust(3) man page.

The rest of the changes are mainly bug fixes and documentation
improvements.

Enjoy!

Mathieu

Project website: http://lttng.org
Documentation: http://lttng.org/docs
Download link: http://lttng.org/download

Changelog:

2017-06-12 (National Peanut Butter Cookie Day) lttng-ust 2.10.0-rc2
        * Introduce LTTNG_UST_ALLOW_BLOCKING env. var.
        * Fix: lttng-ust-elf.c: define NT_GNU_BUILD_ID if not defined
        * Fix: Quote CMAKE variable assignment in Makefile
        * Rework configure script
        * Fix: Typo in doc/examples/Makefile.am
        * Fix: Don't override user variables within the build system
        * Move m4 scripts to m4 dir
        * doc: remove duplicate LTTNG_UST_BLOCKING_RETRY_TIMEOUT man page entry

2017-06-12 (National Peanut Butter Cookie Day) lttng-ust 2.9.1
        * Fix: lttng-ust-elf.c: define NT_GNU_BUILD_ID if not defined
        * Fix: Quote CMAKE variable assignment in Makefile
        * Fix: Typo in doc/examples/Makefile.am
        * Fix: Don't override user variables within the build system
        * Fix: add missing getenv.h include to ustctl.c
        * Fix: race between lttng-ust getenv() and application setenv()
        * doc/man: add typical `$` and `#` prompts to command lines
        * Fix: (un)install targets of Python agent
        * Fix: include config.h to resolve HAVE_DLMOPEN
        * Validate the presence of dlmopen at configure time
        * Fix: CMake examples integration
        * doc/examples/Makefile.am: define C and C++ compilers for CMake

2017-06-12 (National Peanut Butter Cookie Day) lttng-ust 2.8.3
        * Fix: lttng-ust-elf.c: define NT_GNU_BUILD_ID if not defined
        * Fix: Don't override user variables within the build system
        * Fix: add missing getenv.h include to ustctl.c
        * Fix: race between lttng-ust getenv() and application setenv()
        * doc/man: add typical `$` and `#` prompts to command lines
        * Fix: (un)install targets of Python agent

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com