On Chip Controller - IBM Power Systems E870 Technical Overview And Introduction

5137ch02.fm
Server power down
If overall data center processor usage is low, workloads can be consolidated on fewer
numbers of servers so that some servers can be turned off completely. Consolidation
makes sense when there are long periods of low usage, such as weekends. Live Partition
Mobility can be used to move workloads to consolidate partitions onto fewer systems,
reducing the number of servers that are powered on and therefore reducing the power
usage.
On POWER8 processor-based systems, several EnergyScale technologies are
embedded in the hardware and do not require an operating system or external
management component. Fan control, environmental monitoring, and system energy
management are controlled by the On Chip Controller (OCC) and associated components.
The power mode can also be set up without external tools, by using the ASMI interface, as
shown in Figure 2-41.
Figure 2-41 Setting the power mode in ASMI

2.13.2 On Chip Controller

To maintain the power dissipation of POWER7+ with its large increase in performance and
bandwidth, POWER8 invested significantly in power management innovations. A new On
Chip Controller (OCC) using an embedded IBM PowerPC core with 512 KB of SRAM runs
real-time control firmware to respond to workload variations by adjusting the per-core
frequency and voltage based on activity, thermal, voltage, and current sensors.
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IBM Power Systems E870 and E880 Technical Overview and Introduction
Draft Document for Review October 14, 2014 10:19 am