This is not SMB-specific, It is the same as what R77.30 main train QoS user can get.
One can get some more details for QoS events by combing QoS log with FW-1 log
(look for example of such combined log below,note that rule name and number are those of FW-1 rulebase)
Some statistics can be obtained by setting “Account” type of QoS log (backed up by setting corresponding FW-1 log).
As for priority queued related information,
Once in ~5 minutes LLQ (low latency queue) log should be generated for priority queue, with some statistics (see below).
Combined FW1 + QoS log:
LLQ log: