how to see status of rollback for smon

select sysdate,b.name useg, b.inst# instid, b.status$ status, a.ktuxeusn
xid_usn, a.ktuxeslt xid_slot, a.ktuxesqn xid_seq, a.ktuxesiz undoblocks
from x$ktuxe a, undo$ b
where a.ktuxesta = 'ACTIVE' and a.ktuxecfl like '%DEAD%'
and a.ktuxeusn = b.us#;