Resource Manager
Groups of users can be placed in resource groups.
These groups can then be allocated resources: percentage of CPU, maximum connection time, undo tablespace etc.
You can have resource groups within resource groups (multi-level).
To Administrate resource groups:
DBMS_RESOURCE_MANAGER
You can grant administration of plans to other users with DBMS_RESOURCE_MANAGER_PRIVS.
Monitoring
To view currently active plans:
SELECT * FROM V$RSRC_PLAN;
View current consumer groups for sessions:
SELECT SID, SERIAL#, USERNAME, RESOURCE_CONSUMER_GROUP FROM V$SESSION;
View all resource plans defined in the database:
SELECT PLAN, COMMENTS, STATUS FROM DBA_RSRC_PLANS;
View consumer groups granted to users or roles:
SELECT * FROM DBA_RSRC_CONSUMER_GROUP_PRIVS;