[lttng-dev] [RELEASE] LTTng-Tools 2.9.0-rc1

[Jérémie Galarneau]

Hey all!

Today marks the release of the first LTTng 2.9 - "Joannès" release
candidate.

This release is named after a Berliner Weisse style beer from the
Trèfle Noir microbrewery in Rouyn-Noranda.

This new release introduces the following major features:

--- Session load overrides ---
The lttng load command now supports the --override-name and
--override-url options which, as their names indicate, now allow a
session configuration's destination and name parameter to be overridden
without editing the configuration file.

--- State Dump Regeneration ---
This release introduces the "lttng regenerate" command which accepts
both metadata and statedump arguments.

lttng regenerate metadata offers the same functionality as introduced
in LTTng 2.8 by the "lttng metadata" command.  However, the
"statedump" option introduced in this release allows users to trigger
a kernel and/or user-space state dump at will which is useful when
capturing a snapshot.

--- Custom perf PMU Counter Support ---
This feature allows enabling perf PMU counters by raw ID in addition
to the generic list already provided. The format for kernel tracing is
"perf:cpu:raw:rNNN:<name>" and "perf:thread:raw:rNNN:<name> for
user-space. The rNNN format is the same as perf-record(1) where NNN is
an hexadecimal event descriptor in the form of umask+eventsel. The
<name> field allows users to associate a "human-readable" name to the
counter.

Example usage on Intel i7-3520M to get the unhalted reference cycles
(eventsel: 0x13c) count at privilege level 0 (umask: 0x00):
$ lttng add-context --kernel --type perf:cpu:raw:r0013c:x86unhalted

Result in the trace: sched_switch: { cpu_id = 3 }, {
perf_cpu_raw_r0013c_x86unhalted = 27632578 }, [...]

--- OS X/macOS Support ---
LTTng 2.9 is the first release to officially support OS X/macOS.  The
current support is limited to the LTTng relay daemon which allows a
smoother integration within a trace analysis workflow, regardless of
the platform used.


We will cover all of these new features in depth in an upcoming post
on the official LTTng blog at lttng.org/blog in time for the final
release.

The official documentation will also be updated to reflect the
addition of these new features.

As always, please report any issue you may encounter to bugs.lttng.org
or on this mailing list.

Project website: https://lttng.org

Download:
https://lttng.org/files/lttng-tools/lttng-tools-2.9.0-rc1.tar.bz2
GPG sig:
https://lttng.org/files/lttng-tools/lttng-tools-2.9.0-rc1.tar.bz2.asc

Looking forward to your feedback!

Jérémie