Calendar

Current Events

3.30

Creating a Sustainable Society

3.16

Sustainable Energy Engineering

2.28

National Science Foundation Day

2.17

Reformulation-Based Approaches to Query Optimization

2.15

FREEDM Day

2.10

WEST: Cloning Data Cache Behavior using Stochastic Traces

2.09

Computer Vision and Image Analysis in the Study of Art

2.08

GSA Social

2.03

Skewed functional processes and their applications

Feedback DVS-EDF Scheduling for Hard Real-time Embedded Systems

Embedded systems have limited energy resources. Recently, dynamic frequency scaling (DFS) and dynamic voltage scaling (DVS) have been added to various embedded processors as a means to increase battery life. A number of scheduling techniques have been developed to exploit DFS and DVS for real-time systems to reduce energy consumption. We enhance the earliest-deadline first (EDF) scheduling to exploit slack time generated by the invocation of the task at multiple frequency levels. Early scaling at a low frequency, determined by a feedback mechanism and facilitated by a slack-passing scheme, capitalizes on high probabilities of a task to finish its execution without utilizing its worst-case execution budget. If a task does not complete at a certain point in time within its low frequency range, the remainder of it continues to execute at a higher frequency. Our experiments demonstrate that the resulting energy savings exceed those of previously published work by up to 34%.