[lttng-dev] LTTng UST structure support

[chafraysse at free.fr]

Hi Jérémie,

Thx for your reply,
I'm doing a mockup on an Ubuntu host for now
Ok for the graph, I cannot embed it in my application though
I wanted that application to directly output CTF (with compound types, 
excluding LTTng) but I guess I'll output it in my format and then 
post-process it in a bt2 graph with a custom source and the ctf sink

Best regards,

Charles

> Hi Charles,
> 
> I can't really comment on what the packages do, but babeltrace2 
> provides those headers under "include/babeltrace2-ctf-writer" since 
> that library is somewhat "grafted" to the project. Which distro are you 
> using?
> 
> As for where to "plug" your bindings, that library is there to maintain 
> compatibility with the ctf-writer library that was provided by 
> Babeltrace 1.x as it had a number of external users. I don't expect it 
> to keep up with new CTF versions.
> 
> A more "future proof" integration point is to write a source component, 
> and instanciate it in a graph configured with the CTF filesystem sink, 
> and feed your events through the graph.
> 
> Let me know if you want more information,
> Jérémie
> 
> --
> Jérémie Galarneau
> EfficiOS Inc.
> https://www.efficios.com
> 
> Le 2023-02-02 17:06, chafraysse at free.fr a écrit :
> Hi,
> 
> So I wrote a draft of Rust lib above ctf-writer, using the apis as
> demonstrated in the ctf-writer test
> For deployment I wanted to use "libbabeltrace2-ctf-writer.so" in the
> "libbabeltrace2-dev" package but I could not locate the matching
> includes in there or in the other babeltrace 2 packages
> Did I miss them somewhere ? Should I have plugged in at another level
> in babeltrace2 ?
> 
> Best regards,
> 
> Charles
> 
> ----- Mail original -----
> De: chafraysse at free.fr
> À: "Mathieu Desnoyers" <mathieu.desnoyers at efficios.com>
> Cc: lttng-dev at lists.lttng.org
> Envoyé: Lundi 16 Janvier 2023 10:38:28
> Objet: Re: [lttng-dev] LTTng UST structure support
> 
> Hi Mathieu,
> 
> Thanks for your reply :)
> I'll stick to bt2 modules in the meantime then
> I'll already be saving a ton of time with those and the CTF spec which
> is great !
> 
> Best regards,
> 
> Charles
> 
> ----- Mail original -----
> De: "Mathieu Desnoyers" <mathieu.desnoyers at efficios.com>
> À: chafraysse at free.fr, lttng-dev at lists.lttng.org
> Envoyé: Jeudi 12 Janvier 2023 21:10:57
> Objet: Re: [lttng-dev] LTTng UST structure support
> 
> On 2023-01-09 09:02, chafraysse--- via lttng-dev wrote:
>> Hi,
>> 
>> I'm looking for a CTF writer to serialize instrumentations in an
>> embedded Linux/Rust framework
>> LTTng UST looked like a very strong option, but I want to serialize
>> structures as CTF compound type structures and I did not see those
>> supported in the doc or api
> 
> This is correct. I am currently working on a new project called
> "libside" (see https://git.efficios.com/?p=libside.git;a=summary) which
> features support for compound types.
> 
> However, we still need to do the heavy-lifting implementation work of
> integrating this with LTTng-UST. This is the plan towards supporting
> compound types in LTTng-UST.
> 
>> I'd love to have confirmation that I did not just miss something :)
>> If LTTng UST is out for me I will probably try to use the ctf-writer
>> module of babeltrace 2 instead
> 
> For now the ctf-writer modules of bt2 would be an alternative to
> consider, but remember that it is not designed for low-impact tracing
> such as lttng-ust. So it depends on how much tracer overhead/runtime
> impact you can afford in your use-case.
> 
> Thanks,
> 
> Mathieu
> 
>> 
>> Best regards,
>> 
>> Charles
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>> lttng-dev at lists.lttng.org
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> 
> --
> Mathieu Desnoyers
> EfficiOS Inc.
> https://www.efficios.com