[lttng-dev] Questions about CTF format

[Diego Dompe]

Hi Mathieu,

Thanks for the help. Here is my list of details:

- Clocks: the spec doesn't explain properly that timestamps are an offset
from the base time of the clock they refer to. Since I was using 64bit
timestamps I somehow assumed that I was using absolute timestamps from the
epoch (although the spec doesn't says it either).

- I saw that the lttng-generated traces for metadata are always a multiple
of 4k in size (at least the ones I generate for either kernel or user
space). I can't find where in the spec it mentions requirements regarding
metadata packet padding. I was generating metadata packets that ended up
right after my TSDL and eclipse wasn't happy about it (although I didn't
try babeltrace). Also I found that the lttng-generated traces have a
"empty" metadata packet after the metadata containing the TSDL, I didn't
find either any documentation regarding this.

Regards,

Diego

On Thu, Jul 5, 2012 at 8:20 AM, Mathieu Desnoyers <
mathieu.desnoyers at efficios.com> wrote:

> * Diego Dompe (ddompe at gmail.com) wrote:
> > Hi,
> >
> > I'm developing a custom tracer for an embedded product that will generate
> > CTF format. I was able to generate generic traces that can be interpreted
> > properly with babeltrace (but not with eclipse, I already file a bug for
> > that), but I found the CTF specification lacking in some aspects (I had
> to
> > peek into lttng-generated CTF traces to figure out some details). I was
> > wondering what is the proper mailing list to clear my questions and
> provide
> > feedback on the CTF specification for improvement in the areas where the
> > documentation is not detailed yet. I don't see any CTF-specific mailing
> > list, it's OK to discuss it here? Or maybe directly with a developer(s)?
>
> Hi Diego,
>
> Yes, this mailing list would be the proper place, along maybe with
> adding the MCA tiwg mailing list in CC, which I'm doing here.
>
> Thanks,
>
> Mathieu
>
> --
> Mathieu Desnoyers
> Operating System Efficiency R&D Consultant
> EfficiOS Inc.
> http://www.efficios.com
>
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