Power-Aware Scheduling in Computing and Communications with QoS Requirements

Speaker:	Fan ZHANG
		Department of Computer Science
		Hong Kong University of Science & Technology

Title:		"Power-Aware Scheduling in Computing and Communications
		 with QoS Requirements"

Date:		Thursday, 28 April 2005

Time:		4:00 - 5:00pm

Venue:		Rm3464 (CS/Maths Conference Room, via lift nos. 25/26)


Abstract:

Driven by the demand for higher computational power and communication
capabilities, the power consumption of electronic computing devices has
increased drastically in the past decade. This calls for innovative and more
energy efficient system designs not only for battery-powered portable
devices but also for computer servers and server clusters that face the
overheating problem. The concept of power-awareness has been incorporated
into today's hardware and software development as an important design
criterion.

Our work focuses on using scheduling techniques to improve energy efficiency
in task processing and wireless data transmission/reception without
violating the QoS requirements of applications. We first address the issue
of power-aware voltage scaling for real-time periodic tasks. The concept of
"blocking-awareness" is introduced in the context of scheduling tasks with
non-preemptible sections. The proposed blocking-aware algorithms dynamically
adjust the processor speed based on run-time blocking occurrences, therefore
they can greatly reduce processor energy consumption over static speed
schemes.

In the second part, we will analyze the energy consumption of receiving
continuous media streams in a WLAN environment. We point out that existing
standards are not energy efficient as they may cause mobile clients to wake
up frequently and wait for an extended period of time before actual data
reception. Combining power-aware scheduling and traffic shaping at the local
proxy server, the propose wireless traffic scheduling schemes minimize the
waiting time of mobile clients and effectively reduce their energy
consumption. Furthermore, we extend our algorithms to take the residue
battery capacities of the clients into consideration so that clients at low
battery level could spend less energy and enjoy a prolonged battery life.

It is our wish that these analyses and algorithms will benefit the design of
energy-efficient computing and wireless communication software systems.




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Biography:

Fan Zhang is currently a PhD candidate in the Department of Computer Science
at HKUST. He received his BS degree in Computer Science from Fudan
University, China. His research interests include power-aware computing,
real-time systems, resource management and wireless networks.