Copyright by William Lloyd Bircher 2010 - The Laboratory for ...

Table 2.4 Laptop System Description
Processor(s) Dual-core 45nM 2.0GHz
Memory 4GB DDR3-1066
CPU Clock Gating and DVFS
DRAM Power Down and Self Refresh
Power
Chipset Link Disconnect
Management
Harddrive Spin Down and ATA modes
Graphics Processor Clock Gating
Graphics RS780
CPU
Chipset
Observable
Memory
Subsystems
Memory Controller
GPU
Disk
2.2 Controlling Temperature, Voltage and Frequency
The development of power and performance models that are sensitive to temperature,
voltage and frequency requires those parameters to be independently controlled. To this
en`d, multiple techniques are employed. The most difficult parameter to control is
temperature. Temperature has a major impact on power consumption due to its
exponential relationship with leakage power. Depending on the intensity, instruction mix
and data use pattern of workloads, temperature and therefore power varies drastically. To
eliminate this effect a closed loop temperature controller is used to regulate processor
package temperature. The controller regulates temperature within 0.1 degree Celsius
from 20C to 100C. It circulates chilled, 20C water to remove heat from the processor
package. Fine-grain control of temperature is provided by a Peltier-effect thermoelectric
cooler. This device can rapidly add or remove heat from the processor package
depending on demand. Workloads that naturally heat the processor above the setpoint,
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