Hi all,
one of the problems when debugging PCU issues is: How to take proper logs on-site where a problem shows up and give them back to the developer(s) for analysis. If you capture the PCU stdout or configure file-based logging, you will have a hard time corellating that with PCAP traces taken on the RLC/MAC side and/or on the Gb side.
Therefore I propose a new idea here and would like to get your review:
What about implementing a "GSMTAP" log target for libosmocore? This way we could encapsulate the log messages into a special GSMTAP message, which would be sent synchronously in the GSMTAP stream together with RLC/MAC messages on the lower end.
The same could in fact be utilized in osmo-bts, too. This way we could capture BTS log/debug output in-order to L1 messages that we receive and transmit.
What do you think about it? I would be willing to draft the GSMTAP sub-header format and write + submit the wireshark dissector, if somebody wants to write libosmocore log target.
Ideally we would log _all_ messages to that target, and include the subsystem and log level in a header field, so the log verbosity could still be adjusted at the point of review, instead only at the time of logging.
Regards, Harald