On energy debt: Managing consumption on evolving software

This paper introduces the concept of energy debt: a new metric, reflecting the implied cost in terms of energy consumption over time, of choosing a flawed implementation of a software system rather than a more robust, yet possibly time consuming, approach. A flawed implementation is considered to contain code smells, known to have a negative influence on the energy consumption. Similar to technical debt, if energy debt is not properly addressed, it can accumulate an energy "interest". This interest will keep increasing as new versions of the software are released, and eventually reach a point where the interest will be higher than the initial energy debt. Addressing the issues/smells at such a point can remove energy debt, at the cost of having already consumed a significant amount of energy which can translate into high costs. We present all underlying concepts of energy debt, bridging the connection with the existing concept of technical debt and show how to compute the energy debt through a motivational example.This work is financed by National Funds through the Portuguese funding agency, FCT - Fundação para a Ciência e a Tecnologia, within project UIDB/50014/2020. The first author is also financed by FCT grant SFRH/BD/132485/2017. The last author is also supported by operation Centro-01-0145-FEDER-000019 - C4 - Centro de Competências em Cloud Computing, cofinanced by the European Regional Development Fund (ERDF) through the Programa Operacional Regional do Centro (Centro 2020), in the scope of the Sistema de Apoio à Investigação Científica e Tecnológica - Programas Integrados de IC&DT

E-Debitum: managing software energy debt

35th IEEE/ACM International Conference on Automated Software Engineering Workshops (ASEW ’20) - International Workshop on Sustainable Software Engineering (SUSTAIN-SE)This paper extends previous work on the concept of a new software energy metric: Energy Debt. This metric is a reflection on the implied cost, in terms of energy consumption over time, of choosing an energy flawed software implementation over a more robust and efficient, yet time consuming, approach. This paper presents the implementation a SonarQube tool called E-Debitum which calculates the energy debt of Android applications throughout their versions. This plugin uses a robust, well defined, and extendable smell catalogue based on current green software literature, with each smell defining the potential energy savings. To conclude, an experimental validation of E-Debitum was executed on 3 popular Android applications with various releases, showing how their energy debt fluctuated throughout releases.This work is financed by National Funds through the Portuguese funding agency, FCT -Fundação para a Ciência e a Tecnologia within project UIDB/50014/2020

GreenSource: A large-scale collection of android code, tests and energy metrics

This paper presents the GreenSource infrastructure: a large body of open source code, executable Android applications, and curated dataset containing energy code metrics. The dataset contains energy metrics obtained by both static analysing the applications' source code and by executing them with available test inputs. To automate the execution of the applications we developed the AnaDroid tool which instruments its code, compiles and executes it with test inputs in any Android device, while collecting energy metrics. GreenSource includes all Android applications included in the MUSE Java source code repository, while AnaDroid implements all Android's energy greedy features described in the literature, GreenSource aims at characterizing energy consumption in the Android ecosystem, providing both Android developers and researchers a setting to reason about energy efficient Android software development.INCT-EN - Instituto Nacional de Ciência e Tecnologia para Excitotoxicidade e Neuroproteção (UID/EEA/50014/2019)This work is financed by National Funds through the Portuguese funding agency, FCT - Fundação para a Ciencia e a Tecnologia within project: ˆ UID/EEA/50014/2019. Second author is also sponsored by FCT grant SFRH/BD/132485/2017. This work is financed by the ERDF – European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation – COMPETE 2020 Programme and by National Funds through the Portuguese funding agency, FCT, within project POCI-01-0145-FEDER016718

SPELLing out energy leaks: Aiding developers locate energy inefficient code

Although hardware is generally seen as the main culprit for a computer's energy usage, software too has a tremendous impact on the energy spent. Unfortunately, there is still not enough support for software developers so they can make their code more energy-aware.This paper proposes a technique to detect energy inefficient fragments in the source code of a software system. Test cases are executed to obtain energy consumption measurements, and a statistical method, based on spectrum-based fault localization, is introduced to relate energy consumption to the source code. The result of our technique is an energy ranking of source code fragments pointing developers to possible energy leaks in their code. This technique was implemented in the SPELL toolkit.Finally, in order to evaluate our technique, we conducted an empirical study where we asked participants to optimize the energy efficiency of a software system using our tool, while also having two other groups using no tool assistance and a profiler, respectively. We showed statistical evidence that developers using our technique were able to improve the energy efficiency by 43% on average, and even out performing a profiler for energy optimization. (C) 2019 Elsevier Inc. All rights reserved.This work is funded by the ERDF -European Regional Development Fund through the Operational Programme for Competitiveness and Internationalization -COMPETE 2020 Programme within project POCI-01-0145-FEDER-006961, and by National Funds through the Portuguese funding agency, FCT -Fundacao para a Ciencia e a Tecnologia within project POCI010145FEDER016718, UID/EEA/50014/2013, and by FCT grant SFRH/BD/132485/2017. This work is also supported by operation Centro010145FEDER000019 -C4 -Centro de Competencias em Cloud Computing, cofinanced by the European Regional Development Fund (ERDF) through the Programa Operacional Regional do Centro (Centro 2020), in the scope of the Sistema de Apoio a Investigacao Cientifica e Tecnologica -Programas Integrados de IC&DT, and the first author was financed by post-doc grant referencia C4_SMDS_L1-1_D

Energy Wars - Chrome vs. Firefox Which browser is more energy efficient?

This paper presents a preliminary study on the energy consump- tion of two popular web browsers. In order to properly measure the energy consumption of both environments, we simulate the usage of various applications, which the goal to mimic typical user interactions and usage. Our preliminary results show interesting findings based on ob- servation, such as what type of interactions generate high peaks of energy consumption, and which browser is overall the most efficient. Our goal with this preliminary study is to show to users how very different the efficiency of web browsers can be, and may serve with advances in this area of study.FCT -Fundação para a Ciência e a Tecnologia (UIDB/50014/2020

Energy efficiency across programming languages: how do energy, time, and memory relate?

This paper presents a study of the runtime, memory usage and energy consumption of twenty seven well-known software languages. We monitor the performance of such languages using ten different programming problems, expressed in each of the languages. Our results show interesting findings, such as, slower/faster languages consuming less/more energy, and how memory usage influences energy consumption. We show how to use our results to provide software engineers support to decide which language to use when energy efficiency is a concern.We would like to thank Luis Cruz (University of Porto) for the help that he provided. This work is financed by the ERDF - European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation - COMPETE 2020 Programme within project POCI-01-0145-FEDER-006961, and by National Funds through the Portuguese funding agency, FCT - Fundacao para a Ciencia e a Tecnologia within project POCI-01-0145-FEDER-016718 and UID/EEA/50014/2013. The first author is also sponsored by FCT grant SFRH/BD/112733/2015

Browser energy efficiency in android

Dissertação de mestrado integrado em Engenharia InformáticaNowadays, there is a massive growth in energy consumption in the IT sector, which is leaving a huge footprint in terms of energy consumption despite its benefits. With this, the topic of energy consumption and how to improve it has become one of the most talked-about topics today. Several developments have been made to find the most efficient solutions to the various problems that users and developers encounter. But this is far from being an easy task for both, as there is still very little information available, or sometimes the solutions don’t meet the needs of each one. With this in mind, this dissertation aims to verify which Browser is more efficient in the Android environment since there is not much information in this area. For this, we selected seven browsers and ran four test scenarios in order to force the browsers. To test, we recorded a script for each Browser in each scenario, trying to mimic the use of a regular user. The RERAN tool was used to record and repeat each script five times, and the Trepn tool was used to monitor it. The results obtained allowed us to conclude which Browser was more efficient among the seven selected.Atualmente, existe um grande crescimento do consumo energetico do sector de IT, que apesar dos seus benefícios, está a deixar uma enorme pegada no que diz respeito ao consumo energetico. Com isto, o tópico do consumo energético e como melhorar começou ser um dos mais falados atualmente. Diversos desenvolvimentos foram feitos neste âmbito de maneira a encontrar as soluções mais eficientes para os diversos problemas que os utilizadores e os programadores encontram. Mas isto está longe de ser uma tarefa fácil tanto para um como para o outro, sendo que ainda existe muita pouca informação disponível ou por vezes as soluções não vão de encontro às necessidades de cada um. Com isto em mente, esta dissertação tem como objetivo verificar qual o browser é mais eficiente no ambiente Android, visto que não existe muita informação nesta área. Para isto, nós selecionamos sete browsers e fizemos quatro cenários de teste, de maneira a forçar os Browsers. De modo a conseguir testar, gravamos um script para cada Browser em cada cenário, tentando imitar a utilização de um utilizador normal. Foi usada a ferramenta RERAN para gravar e repetir cinco vezes cada script e para a sua monitorização é usado a ferramenta Trepn. Os resultados obtidos permitiram concluir um ranking de qual o Browser foi mais eficiente entre os sete selecionados