Prof. Dr. Frank Bellosa, Dr. Andreas Weißel

Abstract: 

Actions usually taken to prevent processors from overheating, such as decreasing the frequency or stopping the execution flow, also degrade performance. Multiprocessor systems, however, offer the possibility of moving the task which caused a processor to overheat away to some other, cooler processor, so throttling becomes only a last resort taken if all of a system's processors are hot. Additionally, the different energy characteristics that different tasks are showing can be exploited, and hot tasks as well as cool tasks can be distributed evenly among all processors.

This work presents a mechanism for determining the energy characteristics of tasks by means of event monitoring counters, and an energy-aware scheduling policy, which strives to assign tasks to processors in a way that balances the power consumption of the processors, so individual processors do not overheat.

We implemented energy-aware scheduling for the Linux kernel. Evaluations show that the overhead incurred by the additional task migrations required for balancing power is negligible, and that, for many scenarios, energy–aware scheduling reduces the need for throttling and thus yields an increase in throughput.

BibTex: 

@diplomathesis{merkel05pmmultiprocsys,
 author = {Andreas Merkel},
 title = {Balancing Power Consumption in Multiprocessor Systems},
 type = {Diploma Thesis},
 address = {System Architecture Group, University of Karlsruhe, Germany},
 month = sep # "~30",
 year = 2005
}