Chu, E.T.-H.E.T.-H.ChuHuang, T.-Y.T.-Y.HuangTsai, C.-H.C.-H.TsaiChen, J.-J.J.-J.ChenTEI-WEI KUO2018-09-102018-09-102009http://www.scopus.com/inward/record.url?eid=2-s2.0-70349576958&partnerID=MN8TOARShttp://scholars.lib.ntu.edu.tw/handle/123456789/349858The I/O subsystem has become a major source of energy consumption in a hard real-time monitoring and control system. To reduce its energy consumption without missing deadlines, a dynamic power management (DPM) policy must carefully consider the power parameters of a device, such as its break-even time and wake-up latency, when switching off idle devices. This problem becomes extremely complicated when dynamic voltage scaling (DVS) is applied to change the execution time of a task. In this paper, we present COLORS, a composite low-power scheduling framework that includes DVS in a DPM policy to maximize the energy reduction on the I/O subsystem. COLORS dynamically predicts the earliest-access time of a device and switches off idle devices. It makes use of both static and dynamic slack time to extend the execution time of a task by DVS, in order to create additional switch-off opportunities. Task workloads, processor profiles, and device characteristics all impact the performance of a low-power real-time algorithm. We also identify a key metric that primarily determines its performance. The experimental results show that, compared with previous work, COLORS achieves additional energy reduction up to 20%, due to the efficient utilization of slack time. © 2009 Springer Science+Business Media, LLC.Dynamic power management; Dynamic voltage scaling; Real-time embedded systems[SDGs]SDG7Access time; Device characteristics; Dynamic power management; Dynamic voltage scaling; Energy consumption; Energy reduction; Execution time; Hard real-time; I/O Device; I/O subsystems; Low Power; Power parameters; Real time algorithms; Real-time embedded systems; Scheduling frameworks; Slack time; Source of energy; Static and dynamic; Task workloads; Wake-up latency; Color; Electric load forecasting; Electric power measurement; Embedded systems; Energy policy; Phase measurement; Switches; Time switches; Voltage stabilizing circuits; Real time systemsjournal article10.1007/s11241-009-9068-7