Green IT and Green Software

Software and IT usage are continuously growing to keep our society active and manage our individual lives. But as they grow, their energy demand is exploding. By 2030, data centers alone will already consume some 10% of the global electricity.1 Including the Internet, telecommunications, and embedded devices, the energy consumption will be one-third of the global demand. Understanding that end users only consume what we offer, it is the community of software developers who must become active in ecologic behaviors. Green IT is the call of today. Each single line of code that we develop today may still be running years from now on zillions of processors, eating energy and contributing to global climate change

Bringing green software to computer science curriculum: perspectives from researchers and educators

Only recently has the software engineering community started conducting research on developing energy efficient software, or green software. This is shadowed when compared to the research already produced in the computer hardware community. While research in green software is rapidly increasing, several recent studies with software engineers show that they still miss techniques, knowledge, and tools to develop greener software. Indeed, all such studies suggest that green software should be part of a modern Computer Science Curriculum. In this paper, we present survey results from both researchers’ and educators’ perspective on green software education. These surveys confirm the lack of courses and educational material for teaching green software in current higher education. Additionally, we highlight three key pedagogical challenges in bringing green software to computer science curriculum and discussed existing solutions to address these key challenges. We firmly believe that “green thinking” and the broad adoption of green software in computer science curriculum can greatly benefit our environment, society, and students in an era where software is everywhere and evolves in an unprecedented speed.Portuguese Funding Agency (FCT - Fundação para a Ciência e a Tecnologia, within project UIDB/50014/2020) and the U.S. National Science Foundation (NSF) under grant no. CNS-1305359. We also thank the reviewers for their valuable comments and acknowledge the support of the Erasmus+ Key Action 2 project No. 2020- 1-PT01-KA203-078646: “SusTrainable - Promoting Sustainability as a Fundamental Driver in Software Development Training and Education"

Dashboard system for measuring green software design

Global ICT industry is claimed to account for approximately 2 percent of global carbon dioxide which is a figure equivalent to the aviation industry. This is due to lack of awareness to reduce the environmental impact of ICT products and services by the ICT industry practitioners. Therefore, we proposed a GreenDash system, a web-based dashboard that provides a platform for software developers to measure green software design. Software developers capable to calculate sustainability of green software design based on the four components of Information System (IS): database, hardware, people and network. GreenDash System helps to assist software developers to ensure that they considered about green software in designing software product and services

GreenSource: repository tailored for green software analysis

Dissertação de mestrado in Computer ScienceBoth energy consumption analysis and energy-aware development have gained the attention of both developers and researchers over the past years. The interest is more notorious due to the proliferation of mobile devices, where energy is a key concern. There is a gap identified in terms of tools and information to detect and identify anomalous energy consumption in Android applications. A large part of the existing tools are based on external hardware (costly solutions in terms of setup-time), through predictive models (requiring previous hardware calibration) or static code analysis methods. We could not identify so far a tool capable of monitor all relevant system resources and components that an application uses and appoint its energy consumption, while being easily integrated with the application and/or with its development environment. Due to the lack of a tool capable of gathering all this information, a natural consequence is the lack of information about the energy consumption of applications and factors that can influence it. This dissertation aims to carry out a study on the energy consumption of applications and mobile devices in the Android platform, having developed in this scope the GreenSource infrastructure, a repository containing the source code, representative metadata and metrics relatively to a large number of applications (and respective execution in physical devices). In order to gather the results, an auxiliary tool has been developed to automatize the process of testing and collect the respective results for each one of the applications. This tool is a software-based solution, allowing to obtain results in terms of consumption through executions made directly on a physical device running the Android platform. The developed framework, the AnaDroid, has the capability to perform static and dynamic analysis of an application, being able to monitor power consumption and usage of resources for each application through tests execution. This is done following a whitebox testing approach, in order to test applications at source code level. It invokes calls to the TrepnLib library at strategic locations of the application code (through instrumentation techniques) to gain control over relevant portions of the source code, like methods and unit tests. In this way the programmer can have results about the use, state and consumption of resources such as energy, CPU, GPU, memory, sensor usage and complexity of developed test cases. The information gathered through the use of the AnaDroid over a large set of applications was stored in GreenSource backend. With the collected results, we expect to be able to characterize and classify applications, as well the tests developed for it. It is intended that this will be made publicly available and serve as a reference for future works and studies.Quer a análise do consumo de energia, quer o desenvolvimento de aplicações com consciência neste sentido têm vindo a cativar a atenção de desenvolvedores e investigadores nos últimos anos. O interesse é mais notório devido à proliferação de dispositivos móveis, onde a energia é uma preocupação fundamental mas ainda pouco explorada. Como tal, existem lacunas identificadas em termos de ferramentas e informações para detectar e identificar o consumo anómalo de energia em aplicações Android. Grande parte das ferramentas existentes são baseadas em hardware externo (soluções dispendiosas em termos de tempo de setup), através de modelos preditivos (que exigem calibração prévia) ou métodos de análise estática de código. Não conseguimos identificar até ao momento uma ferramenta capaz de monitorizar de forma precisa todos os recursos e componentes relevantes do sistema usados por uma aplicação, bem como de determinar o seu consumo energético. Esta lacuna tem como consequência natural a falta de informação sobre o consumo de energia de aplicações e fatores que podem influenciá-lo. Esta dissertação tem como objetivo realizar um estudo sobre o consumo de energia na plataforma Android, tendo sido desenvolvido neste âmbito a infraestrutura GreenSource. Esta contém um repositório que engloba o código fonte, resultados e métricas relativas a um grande número de aplicações. A fim de obter resultados ilustrativos para um grande número de aplicações, foi desenvolvida uma ferramenta para automatizar o processo de teste e reunir os respectivos resultados. A ferramenta desenvolvida é baseada em software, permitindo obter resultados em termos de consumo através de execuções realizadas diretamente num dispositivo físico Android. Esta framework, denominada AnaDroid, possui a capacidade de analizar aplicações de forma estática e dinâmica, bem como de monitorizar o consumo e uso de recursos durante a sua execução. Para este efeito, são efetuadas invocações a uma biblioteca denominada TrepnLib, em locais estratégicos do código da aplicação para obter controlo sobre partes relevantes deste. Desta forma obtém-se resultados sobre o uso, estado e consumo de recursos, tais como consumo energético, CPU, GPU, memória, sensores. As informações reunidas através da execução do AnaDroid foram armazenadas na base de dados do GreenSource. Com todos os resultados coletados, pretende-se caracterizar e classificar energeticamente aplicações e testes desenvolvidos para estas. Pretende-se disponibilizar abertamente estes resultados, para que possam servir como referencia para futuros trabalhos, análises e estudos

Energyware engineering: techniques and tools for green software development

Tese de Doutoramento em Informática (MAP-i)Energy consumption is nowadays one of the most important concerns worldwide. While hardware is generally seen as the main culprit for a computer’s energy usage, software too has a tremendous impact on the energy spent, as it can cancel the efficiency introduced by the hardware. Green Computing is not a newfield of study, but the focus has been, until recently, on hardware. While there has been advancements in Green Software techniques, there is still not enough support for software developers so they can make their code more energy-aware, with various studies arguing there is both a lack of knowledge and lack of tools for energy-aware development. This thesis intends to tackle these two problems and aims at further pushing forward research on Green Software. This software energy consumption issue is faced as a software engineering question. By using systematic, disciplined, and quantifiable approaches to the development, operation, and maintenance of software we defined several techniques, methodologies, and tools within this document. These focus on providing software developers more knowledge and tools to help with energy-aware software development, or Energyware Engineering. Insights are provided on the energy influence of several stages performed during a software’s development process. We look at the energy efficiency of various popular programming languages, understanding which are the most appropriate if a developer’s concern is energy consumption. A detailed study on the energy profiles of different Java data structures is also presented, alongwith a technique and tool, further providing more knowledge on what energy efficient alternatives a developer has to choose from. To help developers with the lack of tools, we defined and implemented a technique to detect energy inefficient fragments within the source code of a software system. This technique and tool has been shown to help developers improve the energy efficiency of their programs, and even outperforming a runtime profiler. Finally, answers are provided to common questions and misconceptions within this field of research, such as the relationship between time and energy, and howone can improve their software’s energy consumption. This thesis provides a great effort to help support both research and education on this topic, helps continue to grow green software out of its infancy, and contributes to solving the lack of knowledge and tools which exist for Energyware Engineering.Hoje em dia o consumo energético é uma das maiores preocupações a nível global. Apesar do hardware ser, de umaforma geral, o principal culpado para o consumo de energia num computador, o software tem também um impacto significativo na energia consumida, pois pode anular, em parte, a eficiência introduzida pelo hardware. Embora Green Computing não seja uma área de investigação nova, o foco tem sido, até recentemente, na componente de hardware. Embora as técnicas de Green Software tenham vindo a evoluir, não há ainda suporte suficiente para que os programadores possam produzir código com consciencialização energética. De facto existemvários estudos que defendem que existe tanto uma falta de conhecimento como uma escassez de ferramentas para o desenvolvimento energeticamente consciente. Esta tese pretende abordar estes dois problemas e tem como foco promover avanços em green software. O tópico do consumo de energia é abordado duma perspectiva de engenharia de software. Através do uso de abordagens sistemáticas, disciplinadas e quantificáveis no processo de desenvolvimento, operação e manutencão de software, foi possível a definição de novas metodologias e ferramentas, apresentadas neste documento. Estas ferramentas e metodologias têm como foco dotar de conhecimento e ferramentas os programadores de software, de modo a suportar um desenvolvimento energeticamente consciente, ou Energyware Engineering. Deste trabalho resulta a compreensão sobre a influência energética a ser usada durante as diferentes fases do processo de desenvolvimento de software. Observamos as linguagens de programação mais populares sobre um ponto de vista de eficiência energética, percebendo quais as mais apropriadas caso o programador tenha uma preocupação com o consumo energético. Apresentamos também um estudo detalhado sobre perfis energéticos de diferentes estruturas de dados em Java, acompanhado por técnicas e ferramentas, fornecendo conhecimento relativo a quais as alternativas energeticamente eficientes que os programadores dispõem. Por forma a ajudar os programadores, definimos e implementamos uma técnica para detetar fragmentos energicamente ineficientes dentro do código fonte de um sistema de software. Esta técnica e ferramenta têm demonstrado ajudar programadores a melhorarem a eficiência energética dos seus programas e em algum casos superando um runtime profiler. Por fim, são dadas respostas a questões e conceções erradamente formuladas dentro desta área de investigação, tais como o relacionamento entre tempo e energia e como é possível melhorar o consumo de energia do software. Foi empregue nesta tese um esforço árduo de suporte tanto na investigação como na educação relativo a este tópico, ajudando à maturação e crescimento de green computing, contribuindo para a resolução da lacuna de conhecimento e ferramentas para suporte a Energyware Engineering.This work is partially funded by FCT – Foundation for Science and Technology, the Portuguese Ministry of Science, Technology and Higher Education, through national funds, and co-financed by the European Social Fund (ESF) through the Operacional Programme for Human Capital (POCH), with scholarship reference SFRH/BD/112733/2015. Additionally, funding was also provided the ERDF – European Regional Development Fund – through the Operational Programmes for Competitiveness and Internationalisation COMPETE and COMPETE 2020, and by the Portuguese Government through FCT project Green Software Lab (ref. POCI-01-0145-FEDER-016718), by the project GreenSSCM - Green Software for Space Missions Control, a project financed by the Innovation Agency, SA, Northern Regional Operational Programme, Financial Incentive Grant Agreement under the Incentive Research and Development System, Project No. 38973, and by the Luso-American Foundation in collaboration with the National Science Foundation with grant FLAD/NSF ref. 300/2015 and ref. 275/2016

A design method for modular energy-aware software

Nowadays achieving green software by reducing the overall energy consumption of the software is becoming more and more important. A well-known solution is to make the software energy-aware by extending its functionality with energy optimizers, which monitor the energy consumption of software and adapt it accordingly. Modular design of energy-aware software is necessary to make the extensions manageable and to cope with the complexity of the software. To this aim, we require suitable methods that guide designers through the necessary design activities and the models that must be prepared during each activity. Despite its importance, such a method is not investigated in the literature. This paper proposes a dedicated design method for energy-aware software, discusses a concrete realization of this method, and—by means of a concrete example—illustrates the suitability of this method in achieving modularity

Towards an Integrated Full-Stack Green Software Development Methodology

Existing green/eco responsible approaches for IT are frequently domain-specific and very focused on one topic. For example, some works are focused on saving energy with better virtual machine management on cloud infrastructures or data management in wireless sensor networks, in order to minimize the data transfers and sensors’ wakeups. Nevertheless, they consider only limited aspects in the whole software development process; indeed, very few researches propose a global approach. In this context, we envision a green development methodology that approaches energy saving aspects from the design phase and at all the system layers (software, hardware, user requirements, execution contexts, etc.), which can provide positive leverage as well as avoid side effects (one decision can be positive at one system layer but may trigger negative impact on other layers). We motivate the interest of this vision and describe key ideas regarding how to address these considerations in the development methodology

Multi-Stage Network Upgrade for Green Software Defined Networking

This thesis addresses three versions of a novel problem, called Green Multi-Stage Upgrade (GMSU), to upgrade legacy networks to Software Defined Networks (SDNs). The three versions, namely GMSU-1, GMSU-2, and GMSU-3, consider legacy networks that support IEEE 802.1AX, where each link contains multiple cables. Each version aims to replace a set of legacy-switches with SDN-switches over multiple stages. The aim is to maximally turn off unused cables adjacent to SDN-switches to save energy

The Influence of Green Strategies Design onto Quality Requirements Prioritization

[Context and Motivation] Modern society is facing important challenges that are critical to improve its environmental performance. The literature reports on many green strategies aimed at reducing energy consumption. However, little research has been carried out so far on including green strategies in software design. [Question/problem] In this paper, we investigate how green software strategies can contribute to, and influence, quality requirements prioritization performed iteratively throughout a service-oriented software design process. [Methodology] In collaboration with a Dutch industry partner, an empirical study was carried out with 19 student teams playing the role of software designers, who completed the design of a real-life project through 7 weekly deliverables. [Principle ideas/results] We identified a list of quality requirements (QRs) that were considered by the teams as part of their architectural decisions when green strategies were introduced. By analyzing relations between QRs and green strategies, our study confirms usability as the most used QR for addressing green strategies that allow to create people awareness. Qualities like reliability, performance, interoperability, scalability and availability emerged as the most relevant for addressing service-awareness green strategies. [Contribution] If used at the beginning of a green software project, our results help including the most relevant QRs for addressing those green software strategies that are e.g. the most domain-generic (like increase carbon footprint awareness, paperless service provisioning, virtualization)