LTTng

Expose information about overwritten stream packets through the LTTng toolchain, from the kernel and user-space tracers, through the consumer daemon and relay damon, down to Babeltrace, the LTTng trace reader.

It will require adding sequence numbering to the trace packets (a 64-bit unsigned integer), which will allow tracking gaps in the sequence, thus informing the Babeltrace end-user about missing packets on the error output.

In addition, expose packet and events discarded information through the LTTng API. LTTng API will allow querying the number of dropped events and discarded packets on a per-channel basis. Also add this information on the LTTng UI. The session list command will be enhanced with this information, showing it in the session list outtput on a per-channel basis. Finally, a warning will be output when stopping and/or destroying a session that had drop packets/discarded events.