HP ProLiant Server Power Management for Red Hat Enterprise Linux 6.x

3
HP Static High
The firmware controls the P-states. The P-state of the processor is static and it is set to
P0 which corresponds to the highest operating frequency supported by the processor.
OS Control
The RHEL 6.x operating system controls the P-states and it manages the
P-states according to the policy set by the administrator via the OS.
For the HP Static Low and HP Static High modes above, you are advised to disable CPC to ensure that the firmware has
exclusive control of the P-states. CPC is located within the Advanced Power Management Options in RBSU. This causes
RHEL 6.x to report in the /var/log/messages file and in the dmesg output that CPU frequency scaling is not utilized
on the server.
The OS Control mode allows the ProLiant platform firmware to delegate the duty of managing P-states to the RHEL 6.x
operating system.
You can adjust the Power Regulator Settings through the RBSU or the HP iLO 4 interface as shown in Figure 1. You must
reboot the system to change the transitions to and from the OS Control mode but you can change the system between
the other three modes dynamically.
Figure 1: Configuring Power Regulator and Power Capping settings via iLO 4
To adjust the CPC setting, you have to access RBSU as shown in Figure 2. Modifying this setting requires a system reboot
for the setting to take effect.