ECE555 Topic Presentation Energy-efficient real-time scheduling Xing Fu 20 September 2008 Acknowledge Dr. Jian-Jia Chen from ETH providing PPT Slides for IEEE RTAS 2007. Outline of Presentation. System-level Energy Management for Periodic Real-Time Tasks
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ECE555 Topic Presentation
Energy-efficient real-time scheduling
20 September 2008
Acknowledge Dr. Jian-Jia Chen from ETH providing PPT Slides for IEEE RTAS 2007
Paper 1: Systematic results. Other related papers can be treated as special cases.
Paper 2: A closely related field: temperature efficient real time scheduling.
1. Main concepts
2. Key ideas
3. Introduction of underlying mathematics if time allowed
System-level Energy Management for Periodic Real-Time Tasks
Guarantee Real Time
speed of all tasks will be
In practice, many task instances (Jobs) complete without presenting their worst-case workload.
On the Minimization of the Instantaneous Temperature for Periodic Real-Time Tasks
The reduction of power is also needed to cut the power bill off
1. Heat is lost via conduction
2. Ambient temperature of the environment is constant.
Generate a feasible schedule SC for a set of tasks T such that Ψ(SC) is minimized.
This is an e-approximation algorithm which means the maximum temperature of the suboptimal scheme is at most e times as any optimal scheme.
is denoted by σi,j
Execute at two consecutive speeds of effective speed sT*so that the utilization is 100% is optimal
Execute at two consecutive speeds of effective speed sT*so that the utilization is 100% and frequently change speeds
Speed transition overhead
When α = 1, β = 0.01, and σi,j = 1 for any 0 < i j ≤ H
M = 3
Algorithm LTF is a 1.13-approximation algorithm
for energy efficiency.
Jian-Jia Chen, Heng-Ruey Hsu, Kai-Hsiang Chuang, Chia-Lin Yang, Ai-Chun Pang, and Tei-Wei Kuo, "Multiprocessor Energy-Efficient Scheduling with Task Migration Considerations", in ECRTS 2004.
Jian-Jia Chen, Heng-Ruey Hsu, and Tei-Wei Kuo, "Leakage-Aware Energy-Efficient Scheduling of Real-Time Tasks in Multiprocessor Systems", in RTAS 2006.
Applying Algorithm LTF for scheduling
 Dynamic and Aggressive Power-Aware Scheduling Techniques for Real-Time Systems
Example, Linear Matrix Inequality.
Examples: Thermal, fault tolerance, through-output.