System-wide energy optimization for multiple DVS components and real-time tasks

Heechul Yun, Po Liang Wu, Anshu Arya, Cheolgi Kim, Tarek Abdelzaher, Lui Sha

Research output: Contribution to journalArticlepeer-review


Most dynamic voltage and frequency scaling (DVS) techniques adjust only CPU parameters; however, recent embedded systems provide multiple adjustable clocks which can be independently tuned. When considering multiple components, energy optimal frequencies depend on task set characteristics such as the number of CPU and memory access cycles. In this work, we propose a realistic energy model considering multiple components with individually adjustable frequencies such as CPUs, system bus and memory, and related task set characteristics. The model is validated on a real platform and shows less than 2% relative error compared to measured values. Based on the proposed energy model, we present an optimal static frequency assignment scheme for multiple DVS components to schedule a set of periodic real-time tasks. We simulate the energy gain of the proposed scheme compared to other DVS schemes for various task and system configurations, showing up to a 20% energy reduction. We also experimentally verify energy savings of the proposed scheme on a real hardware platform.

Original languageEnglish (US)
Pages (from-to)489-515
Number of pages27
JournalReal-Time Systems
Issue number5
StatePublished - Sep 2011


  • Dynamic voltage scaling (DVS)
  • Energy model
  • Multi-DVS
  • Real-time task scheduling

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Modeling and Simulation
  • Computer Science Applications
  • Computer Networks and Communications
  • Control and Optimization
  • Electrical and Electronic Engineering


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