  Dynamic voltage scaling (DVS) is one of the most effective techniques for
reducing energy consumption in embedded and real-time systems. However,
traditional DVS algorithms have inherent limitations on their capability in
energy saving since they rarely take into account the actual application
requirements and often exploit fixed timing constraints of real-time tasks.
Taking advantage of application adaptation, an enhanced energy-aware feedback
scheduling (EEAFS) scheme is proposed, which integrates feedback scheduling
with DVS. To achieve further reduction in energy consumption over pure DVS
while not jeopardizing the quality of control, the sampling period of each
control loop is adapted to its actual control performance, thus exploring
flexible timing constraints on control tasks. Extensive simulation results are
given to demonstrate the effectiveness of EEAFS under different scenarios.
Compared with the optimal pure DVS scheme, EEAFS saves much more energy while
yielding comparable control performance.
