Notice messages in the event log:
02/22/06 01:48 Notice: sp_cop object ID
cop_objid=SP_OBJECTID=0x0a091559+PN+*+sp_cnc+0xa091559 [sp_cop/19070]
The messages are triggered every time sp_cop launches a new object. The frequency of logging would depend on how often a new object gets launched.
These are additional debug notice messages, this has been addressed in Version 5.1.7.