低耗電即時系統之動態CPU和I/O裝置電壓調整

Dynamic CPU and I/O Device Voltage Scheduling for Low Power Real-Time Systems

陳宏明(Hung-Ming Chen)

指導教授 ： 王勝德

國立臺灣大學/電機資訊學院/電機工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.00233

摘要

在這篇論文中，我們提出非貪婪(non-greedy)的處理器動態電壓調整(Dynamic Voltage Scaling)演算法，稱為”整合處理器與周邊裝置動態電壓調整” (Integrated processor and devices DVS, IDVS)。它針對減少過去動態電壓調節技術儘可能貪婪地調降處理器速度所引起額外的周邊裝置耗能。在過去的研究中，僅僅考慮處理器減速來降低處理器耗能，卻忽略了工作的執行可能會使用到其他的周邊裝置，處理器減速造成工作執行時間變長，使得週邊裝置的使用時間增加。這將有可能會造成在處理器上省下的能源反而從週邊裝置浪費掉。為了做整個系統處理器與裝置的排程，我們分別修改了MUSCLES與LEDES兩種週邊裝置排程的演算法來與我們的處理器動態電壓調整演算法一起工作，藉以觀察延長工作時間對於整個系統耗能的影響。

關鍵字

即時系統 ； 能量耗損 ； 電源管理 ； 週邊裝置

並列摘要

In this thesis, we present a class of non-greedy dynamic voltage scaling algorithms called Integrated processor and devices DVS (IDVS) that is aimed to reduce extra energy consumption caused by the greedy DVS approach. The greedy DVS method tries to reduce the processor power consumption but may increase devices working time. The greedy DVS algorithm simply exploits available slack time while the proposed non-greedy DVS determines the processor operating speed and voltage with the consideration of the used I/O device power consumption. Therefore, it tried to determine the optimal task execution time that minimizes energy consumption of the overall system. We also modified the device scheduling algorithms MUSCLES and LEDES and we made them work with DVS technique to save energy consumption of processor and devices. The proposed approach is called look ahead LEDES (L-LEDES) and look ahead MUSCLES (L-MUSCLES), and they guarantee that no task deadlines are missed due to device transition overhead. L-MUSCLES makes use of a technique that gathers long enough pieces of task execution time or inter-task time and determines the devices wake-up/sleeping time at legal scheduling instant. Simulation results show that the proposed algorithms can reduce energy consumption of the overall system for real-time systems without violating real-time requirements.

並列關鍵字

transition ； power management ； DVS ； DPM ； real time

參考文獻

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