Hi,
See if this helps
a. Find the session id of the dbcc command being run.
b. Use the session id below -
select percent_complete from sys.dm_exec_requests where session_id=xxx
The percent complete returns the % of work completed for most of the tasks being performed.
It can be used to find the backup, restore rollback % as well.
You might want to return some othet columns in the query.
Detailed read available at -
Regards