GSoC Project | Basic Support for Trace Compass

[Ravindra Kumar Meena]

On Mon, Jun 24, 2019 at 12:06 PM Sebastian Huber <
sebastian.huber at embedded-brains.de> wrote:

> On 24/06/2019 08:24, Ravindra Kumar Meena wrote:
> > *Plan of the week:*
> > Last I was able to store the event stream in the disk. Now, I plan to
> > convert the native stream into CTF format. Once the conversion is done
> > then I will make the metadata for the converted CTF format.
>
> The metadata is an essential part of CTF, so you cannot to this after a
> conversion. The metadata must describe your event stream. Please read
> the CTF specification again:
>
> https://diamon.org/ctf/
>
> All what you need to know about the metadata is described in this
> specification in detail. You should be able to write the metadata for an
> event stream consisting of struct ctf_event items until this Wednesday
> so that babeltrace can read it.
>

Okay. I have figured out something very important.

Babeltrace reads trace files only when the event stream file have ctf magic
number(0xc1fc1fc1) and stream id(0000 0000 0000 0000 0000 0000).

The stream data we are generating does not have these. I manually added
these values in the stream file. Babeltrace was reading the trace stream.

This reduced the babeltrace error from

[error] Invalid magic number 0x30302E30 at packet 0 (file offset 0).
[error] Stream index creation error.
[error] Open file stream error.
[warning] [Context] Cannot open_trace of format ctf at path ctf.
[warning] [Context] cannot open trace "ctf" from ctf/ for reading.
[error] Cannot open any trace for reading.
[error] opening trace "ctf/" for reading.
[error] none of the specified trace paths could be opened.

to

[warning] Unknown value 155263 in enum.
0 RTEMS_RECORDING_EVENT: { ns = 0, cpu = 0, events = ( <unknown> :
container = 155263 ), data = 0 }
[error] Event id 216 is outside range.
[error] Reading event failed.
Error printing trace.

As you can see magic number and many others error are reduced. This proves
that we have to add ctf magic number(0xc1fc1fc1) and stream id(0000 0000
0000 0000 0000 0000) in the generated stream file.

-- 
*Ravindra Kumar Meena*,
B. Tech. Computer Science and Engineering,
Indian Institute of Technology (Indian School of Mines)
<https://www.iitism.ac.in/>, Dhanbad
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