[lttng-dev] babeltrace

[Jérémie Galarneau]

Hi Jessica,

I suggest you start by looking at this example in Babeltrace's
tree[1]. These will show you how to read a CTF trace's events from a
Python script.

As for formatting the events as CSV, there is a section dedicated to
this topic in Python's documentation [2].

Regards,
Jérémie

[1] https://bugs.lttng.org/projects/babeltrace/repository/revisions/master/entry/bindings/python/examples/example-api-test.py
[2] https://docs.python.org/3.4/library/csv.html

On Mon, May 12, 2014 at 7:24 PM, Jessica Foest <jessica.foest at gmail.com> wrote:
> Thanks for your detailed responses :)
> Actually i will begin by taking my own trace that i will configure it in
> advance ( same event type , and i will add the different event context that
> i need ) .
> It's my first time to develop with python and i don't really know the
> architecture of babeltrace , So can you help me and tell me how to proceed
> to filter my data from CTF to the output Format that i will choose ?
> I'm only interested on kernel space tracing .
>
>
> 2014-05-08 17:29 GMT-04:00 Jessica Foest <jessica.foest at gmail.com>:
>
>> i work only on kernel space event .
>>
>>
>> 2014-05-08 17:10 GMT-04:00 Jessica Foest <jessica.foest at gmail.com>:
>>
>>> Thanks for your detailed responses :)
>>> Actually i will begin by taking my own trace that i will configure it in
>>> advance ( same event type , and i will add the different event context that
>>> i need ) .
>>> It's my first time to develop with python and i don't really know the
>>> architecture of babeltrace , So can you help me and tell me how to proceed
>>> to filter my data from CTF to the output Format that i will choose ?
>>>
>>>
>>> 2014-05-08 11:53 GMT-04:00 Alexandre Montplaisir
>>> <alexmonthy at voxpopuli.im>:
>>>
>>>>
>>>>> To avoid doing a complete first pass of the trace, you can just
>>>>> iterate on the event types as described in the metadata, and take note
>>>>> of all the possible field you can find in the trace. Then, during your
>>>>> only pass, you already know all your "columns".
>>>>
>>>>
>>>> That's true. Although right now TMF doesn't have an API to ask a trace
>>>> "give me all the event types you have", other than just reading the trace ;)
>>>>
>>>> wrt CTF, it's possible to have events in the metadata that don't
>>>> actually show up in the trace. But that's not really a problem, at worst
>>>> you'd end up with empty columns.
>>>
>>>
>>
>



-- 
Jérémie Galarneau
EfficiOS Inc.
http://www.efficios.com