Overview
The LTTng project aims at providing highly efficient tracing tools for Linux. Its tracers help tracking down performance issues and debugging problems involving multiple concurrent processes and threads. Tracing across multiple systems is also possible.
Apart from LTTng's kernel tracer and userspace tracer, viewing and analysis tools are part of the project. The LTTV viewer permits to analyze and show traces, both in text format and graphically.
LTTng's performance relies on techniques such as Userspace RCU, lockless algorithms, per-cpu data structures and cache impact minimization.
Getting started with LTTng 2.x
Start by looking at the LTTng 2.x page to find out how to deploy LTTng 2.x on your system or you can go directly to the Download section.
Project Updates
LTTng-tools 2.2.0 RC2
Quite a lot of fixes went into this release. For more information, see the changelog.
One thing worth noting is that now the lttng UI will round up subbuffer size to the next power of 2 if needed and warn you about it. Here is an example with enable-channel:
$ lttng enable-channel --subbuf-size 15000 chan1 -u
Warning: The subbuf size (15000) is rounded to the next power of 2 (16384)
Available in the Download section.
LTTng-UST 2.2.0-rc2
A few fixes went into this release: ABI fixes between 2.1 and 2.2, provider compatibility check and a timer management synchronization fix. Also a few optimisation for tracepoint callsite lookup were added.
Changelog:
2013-05-09 lttng-ust 2.2.0-rc2
Available in the Download section.
LTTng-modules 2.2.0-rc2
A few fixes went into this release, mostly kernel 3.9 block layer instrumentation fixes and a vmalloc failure fix on ARM systems.
Changelog:
2013-05-09 LTTng modules 2.2.0-rc2
Available in the Download section.
LTTng officially accepted to Google Summer of Code 2013!
The LTTng team is thrilled to announce that our organization has been officially accepted to Google Summer of Code 2013!
Interested students can consult the ideas list on the LTTng Google Summer of Code 2013 Wiki to get familiar with the proposed projects and begin to interact with the community and craft their proposal.
More information on Google Summer of Code 2013: GSoC 2013 Website
LTTng-modules 2.2.0 RC1
Noteworthy changes:
- Many new subsystems are instrumented. Thanks to Mentor Graphics for
the patches.
Changelog:
2013-03-29 LTTng modules 2.2.0-rc1
Available in the Download section.
LTTng-tools 2.2.0 RC1
Introducing "Cuda", the 2.2.0-rc1 release. Use "lttng version" for a
full description of the codename.
We are now in feature freeze for 2.2 and this is the release candidate
1. Some bugs are still in the pipe in the bug tracker but the new
features are now usable and ready for your precious testing! The
following ChangeLog lists what was added in this version.
2013-03-28 lttng-tools 2.2.0-rc1
The major addition is the UST per UID buffers which can be used like this:
$ lttng create
$ lttng enable-channel chan1 -u --buffers-uid
From this point on, the session only support per UID channel. Per PID
and per UID buffers can NOT coexist.
$ lttng enable-event -a -u -c chan1
$ lttng start
...
Every application sharing the same UID will use the same buffers.
Furthermore, you can now set the attributes of the channel metadata.
This is particularly useful with the periodical flush that was added for
the metadata. For instance:
$ lttng enable-channel metadata --switch-timer 200000 -u
Also, the buffers for UST application are now created in the consumer
and passed to the application. Thus, the buffer ownership has been
transfered from the UST tracer to the consumer.
Finally, the new feature worth noting is the trace file rotation. The -C
and -W option are added to the enable-channel command and control the
maximum size of trace files and the maximum number of them. See man
lttng.1 for more details.
Available in the Download section.
LTTng-UST 2.2.0 RC1
Major new features:
- Per context filtering (vtid, vpid, procname) with e.g.
--filter 'procname=="apache2"'
- Buffers shared across applications with same user id e.g.
lttng enable-channel -u mychan --buffers-uid
- Implement --switch-timer and --read-timer options (periodical flush
and RT-awareness).
- Function entry/exit tracing (see lttng-ust-cyg-profile(3) manpage).
Release name: Cuda
Description (Cuda):
Brewed at the Benelux microbrewery, this IPA has huge floral, citric and
resinous hop aroma, simply an amazing nose. The flavor is very fresh
with a light caramel malting touch completing a strong body. Huge
amounts of hops, lots of grapefruit, lemon and oranges. This is an
outstanding IPA!
Changelog:
2013-03-28 lttng-ust 2.2.0-rc1
Available in the Download section.
LTTng UST 2.1.2
Minor fixes.
Changelog:
2013-03-25 lttng-ust 2.1.2
Available in the Download section.
Babeltrace 1.1.0
Noteworthy changes:
We had to make important namespacing changes to the user-visible API
between babeltrace 1.0.x and 1.1.0 in order to ensure libbabeltrace does
not clash with external project symbols and types.
Changelog:
2013-03-23 Babeltrace 1.1.0
Available in the Download section.
LTTng and Google Summer of Code 2013
The LTTng project is hoping to participate in the Google Summer of Code 2013. Mentoring organisation will be notified of their acceptance in the program on April 8 2013.
Meanwhile, interested students can consult the ideas list on the LTTng Google Summer of Code 2013 Wiki to get familiar with the proposed projects and begin to interact with the community and craft their proposal.
More information on Google Summer of Code 2013: GSoC 2013 Website
