[lttng-dev] [barectf] Filter trace messages based on log level

[Owen, Mark (US)]

Hi,

Thank you for your work on barectf!

I'm considering using it with our embedded MCUs that run on bare metal in
conjunction with other devices running embedded Linux. The barectf platform back
end would primarily be async serial that would be consumed by a device running
embedded Linux.

Our current home brew trace implementation is limited to a logging a log level
and a message string. I see great potential in being able to use the CTF format
to output much more information when events occur than just a level and a
string. My primary concern with barectf is that our current trace implementation
allows us to filter out packets based on log level. I believe this will be
necessary for us not to exceed our bandwidth limitation (the serial port may
also need to be shared for telemetry and command messaging).

My question is, do you think barectf is a good fit for filtering packets based
on a logging level? If so, where would you suggest implementing said filtering
(e.g. extending the platform API or use a custom API in the specific platform
implementation)?

I see that the platform API supports enabling or disabling tracing but I am
looking for something more granular. Is this something that make sense to be
implemented in the platform implementation? My initial thought is that we would
probably need to extend our barectf platform, back end implementation to include
methods for setting the logging filter level.

Before I moved forward I wanted to get your input. Any guidance you could
provide here would be very helpful.

Thank you,

Mark Owen



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