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 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 Massive MIMO: Achievable Energy Efficiency for 5G systems with Multi-user Environment

2019 ◽  
Vol 8 (2) ◽  
pp. 6527-6534
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Path Loss ◽  
Antenna System ◽  
Base Station ◽  
Small Cells ◽  
Limiting Factors ◽  
Improve Energy Efficiency ◽  
User Terminal ◽  
Simulation Results

Massive Multi-Input and Multi-Output (MIMO) antenna system potentially provides a promising solution to improve energy efficiency (EE) for 5G wireless systems. The aim of this paper is to enhance EE and its limiting factors are explored. The maximum EE of 48 Mbit/Joule was achieved with 15 user terminal (UT)s. This problem is related to the uplink spectral efficiency with upper bound for future wireless networks. The maximal EE is obtained by optimizing a number of base station (BS) antennas, pilot reuse factor, and BSs density. We presented a power consumption model by deriving Shannon capacity calculations with closed-form expressions. The simulation result highlights the EE maximization with optimizing variables of circuit power consumption, hardware impairments, and path-loss exponent. Small cells achieve high EE and saturate to a constant value with BSs density. The MRC scheme achieves maximum EE of 36 Mbit/Joule with 12 UTs. The simulation results show that peak EE is obtained by deploying massive BS antennas, where the interference and pilot contamination are mitigated by coherent processing. The simulation results were implemented by using MATLAB 2018b.

scholarly journals The Numerical Simulation of the Airflow Distribution and Energy Efficiency in Data Centers with Three Types of Aisle Layout

2019 ◽  
Vol 11 (18) ◽  
pp. 4937 ◽  
Author(s):  
Jing Ni ◽  
Bowen Jin ◽  
Shanglei Ning ◽  
Xiaowei Wang
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Air Conditioning ◽  
Data Centers ◽  
Simulation Method ◽  
Cooling Capacity ◽  
Energy Utilization ◽  
Improve Energy Efficiency ◽  
Electricity Cost ◽  
Airflow Distribution

The energy consumption of fast-growing data centers is drawing attentions from not only energy organizations and institutions all over the world, but also charity groups, such as Greenpeace, and research shows that the power consumption of air conditioning makes up a large proportion of the electricity cost in data centers. Therefore, more detailed investigations of air conditioning power consumption are warranted. Three types of airflow distributions with different aisle layouts (the open aisle, the closed cold aisle, and the closed hot aisle) were investigated with Computational Fluid Dynamics (CFD) methods in a typical data center of four rows of racks in this study. To evaluate the results of thermal and bypass phenomenon, the temperature increase index (β) and the energy utilization index (ηr) were used. The simulations show that there is a better trend of the β index and ηr index both closed cold aisle and closed hot aisle compared with free open aisle. Especially with high air flow rate, the β index decreases and the ηr index increases considerably. Moreover, the results prove the closed aisles (both closed cold aisle and closed hot aisle) can not only significantly improve the airflow distribution, but also reduce the mixture of cold and heat flow, and therefore improve energy efficiency. In addition, it proves the design of the closed aisles can meet the increasing density of installations and our simulation method could evaluate the cooling capacity easily.

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.

scholarly journals Cell Throughput based Sleep Control Scheme for Heterogeneous Cellular Networks

2018 ◽  
Vol 12 (1) ◽  
pp. 26-33
Author(s):  
Prapassorn Phaiwitthayaphorn ◽  
Kazuo Mori ◽  
Hideo Kobayashi ◽  
Pisit Boonsrimuang
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Cellular Networks ◽  
Operating Cost ◽  
Reducing Power ◽  
Network Capacity ◽  
Base Station ◽  
Base Stations ◽  
Improve Energy Efficiency ◽  
Sleep Control

The mobile traffic continuously grows at a rapid rate driven by the widespread use of wireless devices. Along with that, the demands for higher data rate and better coverage lead to increase in power consumption and operating cost of network infrastructure. The concept of heterogeneous networks (HetNets) has been proposed as a promising approach to provide higher coverage and capacity for cellular networks. HetNet is an advanced network consisting of multiple kinds of base stations, i.e., macro base station (MBS), and small base station (SBS). The overlay of many SBSs into the MBS coverage can provide higher network capacity and better coverage in cellular networks. However, the dense deployment of SBSs would cause an increase in the power consumption, leading to a decrease in the energy efficiency in downlink cellular networks. Another technique to improve energy efficiency while reducing power consumption in the network is to introduce sleep control for SBSs. This paper proposes cell throughput based sleep control which the cell capacity ratio for the SBSs is employed as decision criteria to put the SBSs into a sleep state. The simulation results for downlink communications demonstrate that the proposed scheme improves the energy efficiency, compared with the conventional scheme.

scholarly journals Web servers energy efficiency under HTTP/2

2016 ◽  
Author(s):  
Varun Sapra ◽  
Abram Hindle
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Task Force ◽  
Transport Layer ◽  
The Internet ◽  
Internet Communication ◽  
Web Servers ◽  
Trip Time ◽  
Transport Layer Security ◽  
Web Experience

Server energy consumption has been a subject of research for more than a decade now. With Internet scaling rapidly all over the world, more servers are being added continuously. With global warming and financial cost associated with running servers, it has now become a more pressing concern to optimize the power consumption of these servers while still not affecting the performance. The optimization that can be carried out at the hardware level has its limits and therefore the onus comes on to the software developers as well to optimize their web interacting services and use protocols that are more efficient. Recently, Internet Engineering Task Force (IETF) formalized the specification for the successor of HTTP/1.1 protocol. Named HTTP/2, it has been projected to overcome all the limitations of HTTP/1.1 protocol for which web services developers have to optimize their applications. Understandably, HTTP/2 has been drawing a lot of interest from users, web administrators to big organizations. With HTTP/2 as the future of the Internet communication and servers acting as the backbone of the Internet, we are interested in knowing if HTTP/2 will provide energy efficiency benefits to servers or it will just improve users web experience. In this paper, we evaluate the energy efficiency of two web servers while they communicate over HTTP/1.1 and HTTP/2 protocol. We also investigate how Transport layer security (TLS) affects the power consumption of the servers. In our tests, we have introduced HTTP/2 features one by one so that readers can see for themselves what benefits the HTTP/2 over HTTP/1.1. Our study suggests that multiplexing and Round Trip time (RTT) are the biggest factors helping HTTP/2 achieve its design goals. We conclude that even with huge TLS associated cost with HTTP/2, on high latency networks it can help servers to be more energy efficient while improving their performance as well.

scholarly journals Web servers energy efficiency under HTTP/2

2016 ◽  
Author(s):  
Varun Sapra ◽  
Abram Hindle
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Task Force ◽  
Transport Layer ◽  
The Internet ◽  
Internet Communication ◽  
Web Servers ◽  
Trip Time ◽  
Transport Layer Security ◽  
Web Experience

Server energy consumption has been a subject of research for more than a decade now. With Internet scaling rapidly all over the world, more servers are being added continuously. With global warming and financial cost associated with running servers, it has now become a more pressing concern to optimize the power consumption of these servers while still not affecting the performance. The optimization that can be carried out at the hardware level has its limits and therefore the onus comes on to the software developers as well to optimize their web interacting services and use protocols that are more efficient. Recently, Internet Engineering Task Force (IETF) formalized the specification for the successor of HTTP/1.1 protocol. Named HTTP/2, it has been projected to overcome all the limitations of HTTP/1.1 protocol for which web services developers have to optimize their applications. Understandably, HTTP/2 has been drawing a lot of interest from users, web administrators to big organizations. With HTTP/2 as the future of the Internet communication and servers acting as the backbone of the Internet, we are interested in knowing if HTTP/2 will provide energy efficiency benefits to servers or it will just improve users web experience. In this paper, we evaluate the energy efficiency of two web servers while they communicate over HTTP/1.1 and HTTP/2 protocol. We also investigate how Transport layer security (TLS) affects the power consumption of the servers. In our tests, we have introduced HTTP/2 features one by one so that readers can see for themselves what benefits the HTTP/2 over HTTP/1.1. Our study suggests that multiplexing and Round Trip time (RTT) are the biggest factors helping HTTP/2 achieve its design goals. We conclude that even with huge TLS associated cost with HTTP/2, on high latency networks it can help servers to be more energy efficient while improving their performance as well.

Identifying Constraints Regarding Power Usage Effectiveness for Data Centers Engaging in Demand Response Programs

2013 ◽  
Vol 284-287 ◽  
pp. 3597-3603
Author(s):  
Cheng Jen Tang ◽  
Miau Ru Dai
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Demand Response ◽  
Data Center ◽  
Data Centers ◽  
Green Building ◽  
Power Demand ◽  
Leed Certification ◽  
Improve Energy Efficiency ◽  
Power Usage Effectiveness

Demand response (DR) is an important ingredient and regarded as the killer application of the emerging smart grid. The continuously growing energy consumption of data centers makes data centers promising candidates with significant potential for DR. Participating in DR programs makes data centers have another finical resource in addition to service income. On the other hand, some government organizations also offer considerable incentives to promote energy saving actions for facilities with some certain certifications. Leadership in Energy and Environmental Design (LEED) rating system developed by U.S. Green Building Council (USGBC) is one of the most popular certification systems. LEED uses Power Usage Effectiveness (PUE) as one of the metrics for quantifying how energy efficient a data center is. The goal of PUE is to improve energy efficiency of a data center. DR programs require participants to temporarily reduce their power demand on some occasions with little concern regarding energy efficiency. To enjoy incentives from LEED certification, data center administrators need to know whether the participation of DR hampers the established PUE of their facilities or not. This paper examines the power consumption models from prior studies, and identifies the constraints introduced by PUE for data centers participating in DR programs. The examination reveals that the ratios of static power consumption to the dynamic power demand range of different types of data center equipment do affect PUE while taking demand reduction efforts. With this finding, facility managers of data centers have a clear picture of what to expect from the DR participation, and what to adjust of their data center equipment.

Energy Reduction of Machine Tools

2012 ◽  
Vol 523-524 ◽  
pp. 985-990 ◽  
Author(s):  
Yohei Oda ◽  
Makoto Fujishima ◽  
Yoshikazu Kawamura ◽  
Morihiro Hideta
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Machine Tool ◽  
Machine Tools ◽  
Great Influence ◽  
Energy Reduction ◽  
Improve Energy Efficiency

Machine tools, which are used in factories for long hours and many years, have a great influence on power consumption of the factories. Therefore, reducing machine tool power consumption is one of the important subjects for today’s machine tool manufacturers. In this paper, we will report on our ongoing efforts to improve energy efficiency of machine tools.

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