The below link is very to understand the performance under #EM12c Provided by oracle, This demonstration shows you how to use AWR Warehouse a new feature of Oracle Enterprise Manager 12c Release 4.
https://www.youtube.com/watch?v=StydMitHtuI&feature=youtu.be
Cheers
Osama Mustafa
https://www.youtube.com/watch?v=StydMitHtuI&feature=youtu.be
Cheers
Osama Mustafa