With the introduction of Oracle VM Server for SPARC 2.2, it includes power management features which can be set via the service processor (ILOM) of the supported SPARC T-Series systems.
Watch this video to learn about the hardware power savings capabilities available on SPARC T4 systems, and how Oracle VM Server for SPARC makes use of them. The video will show you how to choose a power management policy and set a power cap.
For more information, read the OTN technical article "How to Use the Power Management Controls on SPARC Servers".
Power Management with Oracle VM Server for SPARC https://blogs.oracle.com/virtualization/entry/power_management_with_oracle_vm