Energy Efficiency in the ICT - Profiling Power Consumption in Desktop Computer Systems

Energy awareness in the ICT has become an important issue. Focusing on software, recent work suggested the existence of a relationship between power consumption, software configuration and usage patterns in computer systems. The aim of this work was collecting and analysing power consumption data of general-purpose computer systems, simulating common usage scenarios, in order to extract a power consumption profile for each scenario. We selected two desktop systems of different generations as test machines. Meanwhile, we developed 11 usage scenarios, and conducted several test runs of them, collecting power consumption data by means of a power meter. Our analysis resulted in an estimation of a power consumption value for each scenario and software application used, obtaining that each single scenario introduced an overhead from 2 to 11 Watts, which corresponds to a percentage increase that can reach up to 20% on recent and more powerful systems. We determined that software and its usage patterns impact consistently on the power consumption of computer systems. Further work will be devoted to evaluate how power consumption is affected by the usage of specific system resource

Reducing Power Consumption in Backbone Networks

Abstract—According to several studies, the power consumption of the Internet accounts for up to 10 % of the worldwide energy consumption, and several initiatives are being put into place to reduce the power consumption of the ICT sector in general. To this goal, we propose a novel approach to switch off network nodes and links while still guaranteeing full connectivity and maximum link utilization. After showing that the problem falls in the class of capacitated multi-commodity flow problems, and therefore it is NP-complete, we propose some heuristic algorithms to solve it. Simulation results in a realistic scenario show that it is possible to reduce the number of links and nodes currently used by up to 30 % and 50 % respectively during off-peak hours, while offering the same service quality

Deskolo : un outil de supervision énergétique pour les parcs informatiques

Session "Démo"National audienceCe projet national, financé par Systematic, a pour vocation de proposer de nouveaux outils logiciels pour la gestion énergétique informatique. En effet, la problématique de la gestion et de l'économie s'avère indispensable à grande échelle, en particulier donc pour des parcs informatiques de centaines d'ordinateurs individuels. Les différentes problématiques abordées dans le cadre de ce projet s'articulent d'une part autour de la caractérisation de la consommation, dans un objectif de supervision, et d'autre part la gestion des machines, afin de réduire la consommation, en particulier pendant les phases d'inactivité des machines, durant la nuit ou les week-ends. La première problématique abordée dans ce projet concerne la caractérisation de la consommation énergétique de chaque machine. En effet, afin de pouvoir estimer la consommation globale du parc uniquement, il est nécessaire de connaître la consommation de chaque machine. Le moyen le plus simple et le plus précis consiste à mesurer à la prise la puissance consommé puis de remonter l'ensemble des mesures à un serveur de données. Cependant cette solution nécessite d'installer un capteur supplémentaire et de gérer l'ensemble du matériel, ce qui rajoute une contrainte physique à la gestion du parc, tout en impliquant un surcoût non négligeable. La solution retenue ici consiste à construire un modèle grâce à des outils d'apprentissage statistique, afin de pouvoir prédire la consommation de chaque machine en utilisant des paramètres facilement accessibles tels que la puissance du processeur, l'activité, etc. L'avantage réside tout d'abord dans l'embarquement très simple du logiciel qui peut tourner en tâche de fond sans impacter l'activité courante. De plus, l'utilisateur peut avoir directement accès à sa consommation et peut estimer la puissance consommée dans sa globalité. L'utilisation de méthodes statistiques permet également d'apprendre différentes fonctions de prédiction selon les modèles de machines disponibles sur le parc. Il est ainsi possible de prendre en considération le vieillissement du matériel et de mettre à jour les modèles utilisés. La méthode utilisée a été développée dans l'article édité sur le site suivant : http://www.wallix.org/2011/08/02/deskolo-project-modeling-the-power-consumption/ L'autre problématique concerne la collecte des données au travers de l'ensemble du parc. Grâce à des outils développés par les partenaires dans le cadre de la supervision et la sécurisation de parc, les données peuvent être centralisées sur le serveur de supervision, tout en conservant l'anonymat puisque seule la puissance électrique est stockée. En fonction des paramètres d'utilisation définis par chaque utilisateur, les ordinateurs peuvent ensuite être systématiquement allumés et éteints chaque jour afin d'optimiser la consommation globale. Différents outils ont été développés durant ce projet, tout d'abord des composants spécifiques pour la supervision, afin de pouvoir communiquer avec chaque machine du réseau, puis des interfaces utilisables localement par chaque utilisateur afin d'avoir une vue de sa consommation, comme l'illustrent les figures ci-dessous. Deux versions ont été développées pour les plateformes Windows et Linux

Low Power Shift and Add Multiplier Design

Today every circuit has to face the power consumption issue for both portable device aiming at large battery life and high end circuits avoiding cooling packages and reliability issues that are too complex. It is generally accepted that during logic synthesis power tracks well with area. This means that a larger design will generally consume more power. The multiplier is an important kernel of digital signal processors. Because of the circuit complexity, the power consumption and area are the two important design considerations of the multiplier. In this paper a low power low area architecture for the shift and add multiplier is proposed. For getting the low power low area architecture, the modifications made to the conventional architecture consist of the reduction in switching activities of the major blocks of the multiplier, which includes the reduction in switching activity of the adder and counter. This architecture avoids the shifting of the multiplier register. The simulation result for 8 bit multipliers shows that the proposed low power architecture lowers the total power consumption by 35.25% and area by 52.72 % when compared to the conventional architecture. Also the reduction in power consumption increases with the increase in bit width.Comment: 11 page

Profiling Power Consumption on Mobile Devices

The proliferation of mobile devices, and the migration of the information access paradigm to mobile platforms, motivate studies of power consumption behaviors with the purpose of increasing the device battery life. The aim of this work is to profile the power consumption of a Samsung Galaxy I7500 and a Samsung Nexus S, in order to understand how such feature has evolved over the years. We performed two experiments: the first one measures consumption for a set of usage scenarios, which represent common daily user activities, while the second one analyzes a context-aware application with a known source code. The first experiment shows that the most recent device in terms of OS and hardware components shows significantly lower consumption than the least recent one. The second experiment shows that the impact of different configurations of the same application causes a different power consumption behavior on both smartphones. Our results show that hardware improvements and energy-aware software applications greatly impact the energy efficiency of mobile device

Modeling Data-Plane Power Consumption of Future Internet Architectures

With current efforts to design Future Internet Architectures (FIAs), the evaluation and comparison of different proposals is an interesting research challenge. Previously, metrics such as bandwidth or latency have commonly been used to compare FIAs to IP networks. We suggest the use of power consumption as a metric to compare FIAs. While low power consumption is an important goal in its own right (as lower energy use translates to smaller environmental impact as well as lower operating costs), power consumption can also serve as a proxy for other metrics such as bandwidth and processor load. Lacking power consumption statistics about either commodity FIA routers or widely deployed FIA testbeds, we propose models for power consumption of FIA routers. Based on our models, we simulate scenarios for measuring power consumption of content delivery in different FIAs. Specifically, we address two questions: 1) which of the proposed FIA candidates achieves the lowest energy footprint; and 2) which set of design choices yields a power-efficient network architecture? Although the lack of real-world data makes numerous assumptions necessary for our analysis, we explore the uncertainty of our calculations through sensitivity analysis of input parameters