[lttng-dev] Iterate events in one packet

Yao Qi yao at codesourcery.com
Wed Feb 27 07:53:13 EST 2013


On 02/27/2013 08:23 PM, Mathieu Desnoyers wrote:
> I'm curious to see what you are trying to achieve by grouping events
> this way ?

We propose to GDB community to save GDB trace data into CTF and read CTF 
data saved by GDB (via libbabeltrace).

   [PATCH 0/5, 2nd try] CTF Support
   http://sourceware.org/ml/gdb-patches/2013-02/msg00669.html

The GDB trace data is composed by several trace frames, and each trace 
frame is composed by several blocks.  When saving GDB trace data into 
CTF, we save the block as ctf event, and save these events belong to the 
same trace frame into one packet, so that the information of the trace 
frame can be saved into packet context.

When reading CTF data, usually we will look for events in current trace 
frame (packet), so that I am asking this question, to see if it is 
easier to do iteration in one packet.

>
> You know you could simply put each logical event group into a different
> "channel" within the same trace, right ?

Can you elaborate a little please?  I am quite new to CTF and babeltrace.

>
> The level of abstraction at which the babeltrace iterator presents the
> trace does not expose details about packet switching. I'd need more
> information to understand the value of your use-case.

Hope my description above is clear.

-- 
Yao (齐尧)



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