Research on power saving and energy efficiency for data-centric computing on production HPC systems

2017 ◽  
Author(s):  
Song Huang
Keyword(s):  
Energy Efficiency ◽  
Power Saving

scholarly journals Power Saving Proxies for Web Servers

2019 ◽  
Vol 63 (2) ◽  
pp. 179-192
Author(s):  
Karl J O’Dwyer ◽  
Eoin Creedon ◽  
Mark Purcell ◽  
David Malone
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Embedded System ◽  
Power Saving ◽  
Web Servers ◽  
Small Energy ◽  
Significant Percentage ◽  
Improve Energy Efficiency ◽  
Data Centre ◽  
Energy Footprint

Abstract Electricity is a major cost in running a data centre, and servers are responsible for a significant percentage of the power consumption. Given the widespread use of HTTP, both as a service and a component of other services, it is worthwhile reducing the power consumption of web servers. In this paper we consider how reverse proxies, commonly used to improve the performance of web servers, might be used to improve energy efficiency. We suggest that when demand on a server is low, it may be possible to switch off servers. In their absence, an embedded system with a small energy footprint could act as a reverse proxy serving commonly-requested content. When new content is required, the reverse proxy can power on the servers to meet this new load. Our results indicate that even with a modest server, we can get a 25% power saving while maintaining acceptable performance.

scholarly journals A survey on software methods to improve the energy efficiency of parallel computing

2016 ◽  
Vol 31 (6) ◽  
pp. 517-549 ◽  
Author(s):  
Chao Jin ◽  
Bronis R de Supinski ◽  
David Abramson ◽  
Heidi Poxon ◽  
Luiz DeRose ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Parallel Computing ◽  
Energy Efficient ◽  
Large Scale ◽  
Energy Use ◽  
Power Saving ◽  
Computing Methods ◽  
Power Budget ◽  
Load Imbalance ◽  
Mixed Precision

Energy consumption is one of the top challenges for achieving the next generation of supercomputing. Codesign of hardware and software is critical for improving energy efficiency (EE) for future large-scale systems. Many architectural power-saving techniques have been developed, and most hardware components are approaching physical limits. Accordingly, parallel computing software, including both applications and systems, should exploit power-saving hardware innovations and manage efficient energy use. In addition, new power-aware parallel computing methods are essential to decrease energy usage further. This article surveys software-based methods that aim to improve EE for parallel computing. It reviews the methods that exploit the characteristics of parallel scientific applications, including load imbalance and mixed precision of floating-point (FP) calculations, to improve EE. In addition, this article summarizes widely used methods to improve power usage at different granularities, such as the whole system and per application. In particular, it describes the most important techniques to measure and to achieve energy-efficient usage of various parallel computing facilities, including processors, memories, and networks. Overall, this article reviews the state-of-the-art of energy-efficient methods for parallel computing to motivate researchers to achieve optimal parallel computing under a power budget constraint.

scholarly journals Improving Energy Efficiency in Idle Listening of IEEE 802.11 WLANs

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Muhammad Adnan ◽  
Eun-Chan Park
Keyword(s):  
Energy Efficiency ◽  
Ieee 802.11 ◽  
Power Saving ◽  
Local Area ◽  
Contention Window ◽  
Channel Access ◽  
Analysis Model ◽  
Frame Aggregation ◽  
Improve Energy Efficiency ◽  
Idle Listening

This paper aims to improve energy efficiency of IEEE 802.11 wireless local area networks (WLANs) by effectively dealing with idle listening (IL), which is required for channel sensing and is unavoidable in a contention-based channel access mechanism. Firstly, we show that IL is a dominant source of energy drain in WLANs and it cannot be effectively alleviated by the power saving mechanism proposed in the IEEE 802.11 standard. To solve this problem, we propose an energy-efficient mechanism that combines three schemes in a systematic way: downclocking, frame aggregation, and contention window adjustment. The downclocking scheme lets a station remain in a semisleep state when overhearing frames destined to neighbor stations, whereby the station consumes the minimal energy without impairing channel access capability. As well as decreasing the channel access overhead, the frame aggregation scheme prolongs the period of semisleep time. Moreover, by controlling the size of contention window based on the number of stations, the proposed mechanism decreases unnecessary IL time due to collision and retransmission. By deriving an analysis model and performing extensive simulations, we confirm that the proposed mechanism significantly improves the energy efficiency and throughput, by up to 2.8 and 1.8 times, respectively, compared to the conventional power saving mechanisms.

Power-Saving Solutions for Pre-Compensated Load-Sensing Systems on Mobile Machines

2021 ◽  
Vol 64 (5) ◽  
pp. 1435-1448
Author(s):  
Xin Tian ◽  
Patrick Stump ◽  
Andrea Vacca ◽  
Stefano Fiorati ◽  
Francesco Pintore
Keyword(s):  
Energy Efficiency ◽  
Hydraulic System ◽  
Power Saving ◽  
Control Valve ◽  
Cost Effective ◽  
Fluid Power ◽  
Flow Control Valve ◽  
List Type ◽  
Load Sensing ◽  
Agricultural Tractors

HighlightsTwo methods (VPM and HVM) are proposed to improve the hydraulic system efficiency of agricultural tractors.VPM and HVM both target reducing the power loss at the flow control valve of the hydraulic system.The solutions are presented conceptually and then numerically modeled, and VPM is tested on an actual tractor.Results show that the VPM solution achieves 6.7% power saving, while HVM achieves 15.6% power saving.Abstract. Load sensing (LS) is a dominant fluid power actuation technology in mobile machines, particularly in construction and agriculture. It has the advantage of guaranteeing good controllability in systems with multiple actuators while promoting higher energy efficiency. Several variants of LS systems have been proposed over the years, and research on cost-effective methods to further increase their efficiency is still of interest for original equipment manufacturers (OEMs) and the fluid power community. This article presents two solution, referred to as variable pump margin (VPM) and hybrid variable margin (HVM), suitable to improve the energy efficiency in pre-compensated LS systems such as those used in agricultural tractors. Both methods allow either downsizing the control valves or reducing the power consumption over the working range. Compared to a standard LS system, the VPM solution lowers the pump pressure using an electronic proportional pressure-reducing valve (ep-PRV), while the HVM solution uses a second ep-PRV in the compensator’s pilot line to further minimize the pressure differential across the LS valve. Simulation and experimental results show that, among the main working conditions, the VPM solution on average achieved 6.7% power saving over the standard LS system, while the model predicted an average improvement of 15.6% for the HVM solution. Keywords: Efficiency, Experiments, Hydraulic, Load sensing, Modeling, Pump.

scholarly journals An Energy-Efficient Strategy for Microcontrollers

2021 ◽  
Vol 11 (6) ◽  
pp. 2581
Author(s):  
Huanjie Wu ◽  
Chun Chen ◽  
Kai Weng
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Low Power ◽  
Power Saving ◽  
Research Direction ◽  
Sleep Time ◽  
Analytical Models ◽  
Clock Frequency ◽  
Improve Energy Efficiency ◽  
Time Required

Power saving has always been an important research direction in the field of microcontrollers. Dozens of low power technologies have been proposed to achieve the goal of reducing their power consumption. However, most of them focus mostly on lowering the consumption rate. It is well known that energy is the integral of power over time. Thus, our view is that both power and time should be carefully considered to achieve better energy efficiency. We reviewed some commonly used low power technologies and proposed our assumptions and strategy for improving energy efficiency. A series of test sets are designed to validate our hypotheses for improving energy efficiency. The experimental results suggest that time has no less impact on energy consumption than power. To support the operation of the processor, some peripheral components consume a constant amount of power regardless of the clock frequency, but the power consumption will be reduced when the processor enters low-power modes. This results in some interesting phenomena that are different from the usual thinking that energy can be saved by increasing processor clock frequency. For STM32F407 and Xtensa LX6 processors, this article also analyzes and calculates the minimum sleep time required for achieving energy saving based on our analytical models. Our energy efficiency strategy has been verified, and in some cases, it can indeed improve energy efficiency. We also proposed some suggestions on hardware design and software development for better energy efficiency.

scholarly journals Spectrum-Aware Energy Efficiency Analysis in K-tier 5G HetNets

Electronics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 839
Author(s):  
Fereidoun H. Panahi ◽  
Farzad H. Panahi ◽  
Tomoaki Ohtsuki
Keyword(s):  
Energy Efficiency ◽  
Power Saving ◽  
Base Stations ◽  
D2d Communication ◽  
Small Cells ◽  
Power Coefficient ◽  
Video Sharing ◽  
Power Saving Mode ◽  
Communication Network Design ◽  
Saving Mode

In future multi-tier cellular networks, cognitive radio (CR) compatible with device-to-device (D2D) communication can be an aid to enhance system spectral efficiency (SE) and energy efficiency (EE). Users in proximity can establish a direct connection with D2D communication and bypass the base stations (BSs), thereby offloading the network infrastructure and providing EE improvement. We use stochastic geometry to model and analyze cognitive D2D communication underlying a multi-tier/multi-channel cellular network where the D2D transmitters are capable of harvesting RF energy from ambient interference resulting from simultaneous cellular downlink transmissions. For further improvement in EE, small cells (SCs) can be put into a power-saving mode by specifying a load-dependent transmission power coefficient (TPC) for SC BSs. In addition, to consider practical D2D communication scenarios, we propose a wireless video sharing framework where cache-enabled users can store and exchange popular video files through D2D communication. We investigate the potential effects of the TPC and the introduced D2D layer on the network EE and SE. We will also observe that the energy-harvesting CR-based D2D communication network design will not only ease the spectrum shortage problem but will also result in a greener network thanks to its reliance on ambient energies.

scholarly journals Matching SDN and Legacy Networking Hardware for Energy Efficiency and Bounded Delay

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3915 ◽  
Author(s):  
Pablo  Fondo-Ferreiro ◽  
Miguel Rodríguez-Pérez ◽  
Manuel  Fernández-Veiga ◽  
Sergio  Herrería-Alonso
Keyword(s):  
Energy Efficiency ◽  
Energy Efficient ◽  
Power Saving ◽  
Environmental Costs ◽  
Delay Sensitive ◽  
Operation Costs ◽  
Energy Efficient Ethernet ◽  
Saving Algorithm ◽  
Theoretical Results ◽  
Qos Metrics

Both economic and environmental costs are driving much research in the area of the energy efficiency of networking equipment. This research has produced a great amount of proposals. However, the majority of them remain unimplemented due to the lack of flexibility of current hardware devices and a certain lack of enthusiasm from commercial vendors. At the same time, Software-Defined Networking (SDN) has allowed customers to control switching decisions with a flexibility and precision previously unheard of. This paper explores the potential convergence between the two aforementioned trends and presents a promising power saving algorithm that can be implemented using standard SDN capabilities of current switches, reducing operation costs on both data centers and wired access networks. In particular, we focus on minimizing the energy consumption in bundles of energy-efficient Ethernet links leveraging SDN. For this, we build on an existing theoretical algorithm and adapt it for implementing with an SDN solution. We study several approaches and compare the resulting algorithms not only according to their energy efficiency, but also taking into account additional QoS metrics. The results show that the resulting algorithm is able to closely match the theoretical results, even when taking into account the requirements of delay-sensitive traffic.

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