[ltt-dev] LTTng traces

Mathieu Desnoyers compudj at krystal.dyndns.org
Thu Jan 29 10:06:26 EST 2009


* Jérôme Stadelmann (jerome.stadelmann at heig-vd.ch) wrote:
> Hi Mathieu,
> 
> Excuse-me for asking again but, is there really no other way to go than scanning the source code in order to understand the traces format and information ?
> For your question, I'm using the version 0.82.
> 

I would recommend :

starting with ltt/ltt-serialize.c : there is a very lengthy comment in
there which explains the format strings and how the generic serializer
writes the event data.

Looking at ltt/probes/ltt-type-serializer.h to see how the specialized
probes write the event information.

And for a more palatable document :

(latest publicly available version of ISO/IEC 9899:1999, Programming
Languages - C)
http://www.open-std.org/JTC1/SC22/WG14/www/docs/n1256.pdf

Section 6.7.2.1 Structure and union specifiers

LTTng event fields follow a subset of the ISO C standard for structures.
Specific note : unlike the standard C implementations, there is no
padding at the end of the event payload (structure). Also note that
LTTng does not support bitfields in C structures because they depend on
the specific compiler implementation.

Hope this helps,

Mathieu

> Best regards,
> Jerome
> 
> Le jeudi 22 janvier 2009 21:07:49 Mathieu Desnoyers, vous avez écrit :
> > * Stadelmann Jérôme (jerome.stadelmann at heig-vd.ch) wrote:
> > > Hi all,
> > > 
> > > I'm trying to parse and decode the trace files but it is not so easy.
> > > Is there a place or a file where I could find a description of all the facilities and the events id's ?
> > > 
> > 
> > In the current LTTng, there is no such thing as "facility" anymore.
> > Which LTTng version are you working with ?
> > 
> > Mathieu
> > 
> > > Thank you
> > > Jerome
> > > 
> > > _______________________________________________
> > > ltt-dev mailing list
> > > ltt-dev at lists.casi.polymtl.ca
> > > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> > > 
> > 
> 

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68




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