Power consumption is an important design parameterfor embedded and portable systems. Software-controlled (or dynamic) power management (DPM) has recently emerged as an attractive alternative to inflexible hardware solutions. DPMfor hard rea I-time systems has received relatively little attention. In particulal: energy-driven I/O device scheduling for real-time systems has not been considered before. We present thejirst online DPM algorithm, which we call Low Energy Device Scheduler (LEDES), for hard realtime systems. LEDES takes as inputs a predetennined task schedule and a device-usage list for each task and it generates a sequence of sleephorking states for each device. It guarantees that real-time constraints are not violated and it also minimizes the energy consumed by the I10 devices used by the task set. LEDES is energy-optimal under the constraint that the start times of the tasks are f i e d . We present a case study to show that LEDES can reduce energy consumption by almost 50%.
Swaminathan et al. REF proposed an offline method for dynamic I/O power management with hard real-time constraints.
Dynamic I/O power management for hard real-time systems
Ninth International Symposium on Hardware/Software Codesign. CODES 2001 (IEEE Cat. No.01TH8571)
Ninth International Symposium on Hardware/Software Codesign. CODES 2001 (IEEE Cat. No.01TH8571)
Computer Science