If you've ever suffered from lost trace event records when using LTTng-UST then you might be interested to know that LTTng 2.10 includes a new feature to prevent that from happening: blocking mode support for channels.
This long-awaited feature makes it possible for LTTng-UST to wait until space becomes available in the trace buffers instead of losing existing event records when new ones arrive.
In my day to day job at EfficiOS, I often have to manually test different versions and configurations of LTTng. The typical way to test LTTng 2.7 if LTTng 2.8 is installed, for example, is, for each of the three LTTng projects (LTTng-tools, LTTng-UST, and LTTng-modules):
This whole manual process becomes painful over time. I'm not even mentioning the situations where I also need to test different versions of the tools' dependencies, like Glib and Libxml2. The same laborious process applies to Babeltrace.
In an ideal world, I would have multiple environments containing
different versions and configurations of the tools and dependencies
which form the LTTng ecosystem. This is totally possible with the
various environment variables and configure flags (--prefix,
--with-lttng-ust-prefix, and the rest) of the projects. And this is
exactly what vlttng exploits to
achieve this. vlttng is a project I've been working on in my spare time.
In this article I explain what vlttng is exactly, after which I show a concrete example.
Hi everyone! Alexandre here.
In this blog post, I will demonstrate how to generate LTTng traces from the Trace Compass viewer using the LTTng-UST Java agent integration. This should effectively explain:
java.util.logging
tracepoints.This is basically an update of Tutorial: Tracing Java Logging Frameworks for LTTng 2.7 and above. I will also go into more details regarding how to use configuration files and how to record Trace Compass traces.
Today I am pleased to announce the release of barectf 2.1!
The major new feature is the ability to include one or more external YAML files as the base properties of the metadata, clock, trace, stream, and event objects.
I wrote a few "standard" partial configuration files which are installed with barectf 2.1.
I moved all the single-page documentation to a more organized project wiki. This could eventually be moved again to a standalone website if need be.
This new version also allows optional object properties to be forced to
their default values by setting them to null, not unlike
CSS3's initial keyword.
This is useful when using
type inheritance
or inclusions, for example:
type-aliases:
base-int:
class: int
size: 23
align: 16
base: oct
child-int:
$inherit: base-int
base: null
In the example above, the child-int type object inherits its parent's
base property (oct), but it's reset to its default value (dec) by
setting it to null.
I also added configuration file tests to the project. The tests are executed by LTTng's CI tool. The testing framework only depends on Bash. Those tests highlighted a bunch of bugs here and there which I fixed.
A summary of the changes is available in the new barectf changelog.
BeagleBone Black with GPIO test circuit.
Embedded systems usually present some kind of constraints, such as
limited computing power, minimal amount of memory, low or nonexistent
storage, etc. Debugging embedded systems within those constraints can be
a real challenge for developers. Sometimes, developers will fallback to
logging to a file with their beloved printf() in order to find the
issues in their software stack. Keeping these log files on the system
might not be possible.
The goal of this post is to describe a way to debug an embedded system with tracing and to stream the resulting traces to a remote machine.