An Operating System Guided Fine-Grained Power Gating Control Based on Runtime Characteristics of Applications

Atsushi KOSHIBA  Mikiko SATO  Kimiyoshi USAMI  Hideharu AMANO  Ryuichi SAKAMOTO  Masaaki KONDO  Hiroshi NAKAMURA  Mitaro NAMIKI  

IEICE TRANSACTIONS on Electronics   Vol.E99-C    No.8    pp.926-935
Publication Date: 2016/08/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E99.C.926
Type of Manuscript: Special Section PAPER (Special Section on Low-Power and High-Speed Chips)
energy conservation,  power gating,  operating system,  microprocessor,  

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Fine-grained power gating (FGPG) is a power-saving technique by switching off circuit blocks while the blocks are idle. Although FGPG can reduce power consumption without compromising computational performance, switching the power supply on and off causes energy overhead. To prevent power increase caused by the energy overhead, in our prior research we proposed an FGPG control method of the operating system(OS) based on pre-analyzing applications' power usage. However, modern computing systems have a wide variety of use cases and run many types of application; this makes it difficult to analyze the behavior of all these applications in advance. This paper therefore proposes a new FGPG control method without profiling application programs in advance. In the new proposed method, the OS monitors a circuit's idle interval periodically while application programs are running. The OS enables FGPG only if the interval time is long enough to reduce the power consumption. The experimental results in this paper show that the proposed method reduces power consumption by 9.8% on average and up to 17.2% at 25°C. The results also show that the proposed method achieves almost the same power-saving efficiency as the previous profile-based method.