We are with Oracle Enterprise Manager 11g Release 1 Grid Control.
As there are many administrators and other users of the GC, what is the way to display info on currently logged - active users?
Something as "Search Sessions" tab for databases -> performance tab.
One way to figure out who are currently logged in is to enable EM auditing on logon and logoff operations, then check audit logs to see who logged on but has not logged out.
For information on setting up EM auditing, see: