[lttng-dev] Tagging traces with arbitrary data (as in custom metadata)

[Mathieu Desnoyers]

----- Original Message -----

> From: "David Lindström" <david.lindstrom at percepio.se>
> To: lttng-dev at lists.lttng.org
> Sent: Tuesday, November 5, 2013 9:15:14 AM
> Subject: [lttng-dev] Tagging traces with arbitrary data (as in custom
> metadata)

> Hi, I was wondering if there’s a way to tag a trace with some additional
> information. A general example would be to include a description of the
> current experiment. One way to do this currently would be to create a custom
> lttng-message application with some UST tracepoint and then just log that to
> a separate channel, but that would be pretty ugly. It would be much cleaner
> to insert extra fields into the metadata stream. Is something like that
> possible in current versions of LTTng and/or would it be possible to add it
> for a future version?

The CTF metadata has an environment (env {}) section that contains this kind of information. LTTng already uses it to store the tracer version and some info about the system. We could eventually add a feature like this, a "tag", that would be added to the CTF environment information. I would guess that users would provide this tag on the lttng command line for their session, and it would be passed to the tracers by sessiond. 

Thoughts ? 

Thanks, 

Mathieu 

> Mvh
> David Lindström

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