Hibernus plus plus : A Self-Calibrating and Adaptive System for Transiently-Powered Embedded Devices
Hibernus plus plus : A Self-Calibrating and Adaptive System for Transiently-Powered Embedded Devices
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DOI：
10.1109/tcad.2016.2547919
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发表时间：
2016-12-01
影响因子：
2.9
通讯作者：
Benini, Luca
中科院分区：
文献类型：
--
作者：
Balsamo, Domenico;Weddell, Alex S.;Benini, Luca
能量采集器被用于为自主系统提供动力，但其输出功率是可变的和间歇性的。为了维持计算，这些系统集成了电池或超级电容器，以平滑收割机输出的快速变化。能量存储设备需要充电时间，并且增加了系统的尺寸、质量和成本。瞬态计算领域不再采用这种方法，而是直接从采集器输出为系统供电。为了防止应用程序在断电后必须重新启动计算，Hibernus等方法允许这些系统在电源故障即将发生时休眠。当电源达到工作阈值时，将恢复上次保存的状态，并从中断点继续运行。本文提出了Hibernus++智能地适应休眠和恢复阈值，以响应源动态和系统负载属性。具体地，在系统中内置了自主表征硬件平台及其在休眠期间的性能的能力，以便将休眠阈值设置在使浪费的能量最小化并使计算时间最大化的点。类似地，系统根据能量供应和消耗的平衡来自动校准恢复阈值，以便最大化计算时间。Hibernus++在微控制器硬件上使用合成和真实的能量采集器进行了理论和实验验证。结果表明，与最先进的方法相比，Hibernus++平均降低了16%的能耗，并将应用程序执行时间缩短了17%。
Energy harvesters are being used to power autonomous systems, but their output power is variable and intermittent. To sustain computation, these systems integrate batteries or supercapacitors to smooth out rapid changes in harvester output. Energy storage devices require time for charging and increase the size, mass, and cost of systems. The field of transient computing moves away from this approach, by powering the system directly from the harvester output. To prevent an application from having to restart computation after a power outage, approaches such as Hibernus allow these systems to hibernate when supply failure is imminent. When the supply reaches the operating threshold, the last saved state is restored and the operation is continued from the point it was interrupted. This paper proposes Hibernus++ to intelligently adapt the hibernate and restore thresholds in response to source dynamics and system load properties. Specifically, capabilities are built into the system to autonomously characterize the hardware platform and its performance during hibernation in order to set the hibernation threshold at a point which minimizes wasted energy and maximizes computation time. Similarly, the system auto-calibrates the restore threshold depending on the balance of energy supply and consumption in order to maximize computation time. Hibernus++ is validated both theoretically and experimentally on microcontroller hardware using both synthesized and real energy harvesters. Results show that Hibernus++ provides an average 16% reduction in energy consumption and an improvement of 17% in application execution time over state-of-the-art approaches.