In this thesis, effects of some software design patterns on real time software performance will be investigated. In real time systems, performance requirements are critical. Real time system developers usually use functional languages to meet the requirements. Using an object oriented language may be expected to reduce performance. However, if suitable software design patterns are applied carefully, the reduction in performance can be avoided. In this thesis, appropriate real time software performance metrics are selected and used to measure the performance of real time software systems.

Developing high quality software is of eminent importance to keep the existing customers satisfied and to remain competitive. One of the most important software quality characteristics is performance, which defines how fast and/or efficiently a software can perform its operation. While several studies have shown that field problems are often due to performance issues instead of feature bugs, prior research typically treats all bugs as similar when studying various aspects of software quality (e.g., predicting the time to fix a bug) or focused on other types of bug (e.g., security bugs). There is little work that studies performance bugs. In this thesis, we perform an empirical study to quantitatively and qualitatively examine performance bugs in the Mozilla Firefox and Google Chrome web browser projects in order to find out if performance bugs are really different from other bugs in practice and to understand the rationale behind those differences. In our quantitative study, we find that performance bugs of the Firefox project take longer time to fix, are fixed by more experienced developers, and require changes to more lines of code. We also study performance bugs relative to security bugs, since security bugs have been extensively studied separately in the past. We find that security bugs are re-opened and tossed more often, are fixed and triaged faster, are fixed by more experienced developers, and are assigned more number of developers in the Firefox project. Google Chrome project also shows different quantitative characteristics between performance and non-performance bugs and from the Firefox project. Based on our quantitative results, we look at that data from a qualitative point of view. As one of our most interesting observation, we find that end-users are often frustrated with performance problems and often threaten to switch to competing software products. To better understand, the rationale for some users being very frustrated (even threatening to switch product) even though most systems are well tested, we performed an additional study. In this final study, we explore a global perspective vs a user centric perspective of analyzing performance data. We find that a user-centric perspective might lead to a small number of users with considerably poor performance while the global perspective might show good or same performance across releases. The results of our studies show that performance bugs are different and should be studied separately in large scale software systems to improve the quality assurance processes related to software performance. / Thesis (Master, Computing) -- Queen's University, 2012-04-30 01:28:22.623

With advances in hardware miniaturization and wireless communication technologies even small portable wireless devices have much communication bandwidth and computing power. These devices include smartphones, tablet computers, and personal digital assistants. Users of these devices expect to run software applications that they usually have on their desktop computers as well as the new applications that are being developed for mobile devices. Web browsing, social networking, gaming, online multimedia playing, global positioning system based navigation, and accessing emails are examples of a few popular applications. Mobile versions of thousands of desktop applications are already available in mobile application markets, and consequently, the expected operational time of smartphones is rising rapidly. At the same time, the complexity of these applications is growing in terms of computation and communication needs, and there is a growing demand for energy in smartphones. However, unlike the exponential growth in computing and communication technologies, in terms of speed and packaging density, battery technology has not kept pace with the rapidly growing energy demand of these devices. Therefore, designers are faced with the need to enhance the battery life of smartphones. Knowledge of how energy is used and lost in the system components of the devices is vital to this end. With this view, we focus on modeling and evaluating the energy performance of smartphones in this thesis. We also propose techniques for enhancing the energy efficiency and functionality of smartphones. The detailed contributions of the thesis are as follows: (i) we present a nite state machine based model to estimate the energy cost of an application running on a smartphone, and provide practical approaches to extract model parameters; (ii) the concept of energy cost pro le is introduced to assess the impact of design decisions on energy cost at an early stage of software design; (iii) a generic architecture is proposed and implemented for enhancing the capabilities of smartphones by sharing resources; (iv) we have analyzed the Internet tra c of smartphones to observe the energy saving potentials, and have studied the implications on the existing energy saving techniques; and nally, (v) we have provided a methodology to select user level test cases for performing energy cost evaluation of applications. All of our concepts and proposed methodology have been validated with extensive measurements on a real test bench. Our work contributes to both theoretical understanding of energy e ciency of software applications and practical methodologies for evaluating energy e ciency. In summary, the results of this work can be used by application developers to make implementation level decisions that affect the energy efficiency of software applications on smartphones. In addition, this work leads to the design and implementation of energy e cient smartphones.

Στην παρούσα εργασία γίνεται μελέτη ορισμένων χαρακτηριστικών παραμέτρων που αποδίδουν ένα ενδεικτικό μέτρο παραμορφώσεων για ηχητικά σήματα. Τα σήματα αυτά είναι παράγωγα διαφόρων λογισμικών ήχου που λειτουργούν σε μεταβλητές καταστάσεις υπολογιστικού φόρτου, με αποτέλεσμα να μελετάται εάν και πώς επηρρεάζονται τα ηχητικά σήματα από τους παράγοντες αυτούς. Γίνεται προσπάθεια να οριστεί κατάλληλος τρόπος αξιολόγησης των λογισμικών ήχου για την περαιτέρω διερεύνηση της υποκειμενικής ηχητικής ποιότητας από κάποια υπολογιστικά συστήματα. / --

Orientador: Rodolfo Jardim de Azevedo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-23T23:05:30Z (GMT). No. of bitstreams: 1 Garcia_LeonardoAugustoGuimaraes_M.pdf: 3415043 bytes, checksum: 9df4293802303aa68e123c48882f387f (MD5) Previous issue date: 2013 / Resumo: A evolução das arquiteturas de computadores nos últimos anos, com a considerável introdução de processadores com vários núcleos e computadores com vários processadores, inclusive em máquinas consideradas de baixo poder de processamento, faz com que seja primordial o desenvolvimento de novos paradigmas e modelos de programação paralela que sejam fáceis de usar e depurar pela grande maioria dos programadores de sistemas. Os modelos de programação paralela, atualmente disponíveis, são baseados em primitivas de implementação cujo uso é complexo, tedioso e altamente sujeito a erros como, por exemplo, locks, semáforos, sinais, mutexes, monitores e threads. Neste cenário, as Memórias Transacionais (TM) aparecem como uma alternativa promissora que promete ser eficiente e, ao mesmo tempo, fácil de programar. Muita pesquisa foi feita nos últimos anos em relação às Memórias Transacionais em Software (STM), a maior parte delas relacionada a seu desempenho, com pouca atenção dada a outras métricas importantes, como, por exemplo, o consumo energético e como este se relaciona com o tempo de execução - energy-delay product (EDP). Esta dissertação de mestrado faz uma avaliação destas métricas em uma STM configurada com diversas políticas de gerenciamento da TM e de utilização energética, sendo algumas destas combinações inéditas. É mostrado que os resultados para desempenho e EDP nem sempre seguem a mesma tendência e, portanto, pode ser apropriado escolher diferentes políticas de gerenciamento dependendo de qual é o foco da otimização que se deseja fazer, sendo que algumas vezes a execução sequencial pode ser melhor que qualquer execução paralela. De uma forma geral, a execução com o uso de TM foi mais rápida quando comparada com a execução sequencial em dois terços dos casos analisados e teve melhor EDP em um terço das execuções. Através desta análise foi possível derivar um conjunto mínimo de políticas de gerenciamento da TM que foram capazes de entregar melhor resultado para o conjunto de benchmarks estudados, além de identificar tendências sobre o comportamento dos sistemas de TM para grupos de benchmarks quando se varia o número de núcleos executando em paralelo e o tamanho da carga de trabalho / Abstract: The recent unveilings on the computer architecture area, with the massive introduction of multi-core processors and computers with many processors in the last years, even in embedded systems, has brought to light the necessity to develop new paradigms and models for parallel programming that could be leveraged and are easy to debug by the majority of the developers. The current parallel programming models are based on primitives whose use is complex, tedious and highly error prone, such as locks, semaphores, signals, mutexes, monitors and threads. In this scenario, the Transactional Memories (TM) appear as a promising alternative which aims to be efficient and, at the same time, easy to program. Lots of research have been made on the past years on Software Transactional Memories (STM), the majority of them interested on the performance of such systems, with little attention given to other metrics such as energy and the relationship between energy and performance, known as the energy-delay product (EDP). This work evaluates these metrics in an STM configured with a number of TM and energy management policies, some of them new. It is shown that performance and EDP do not always follow the same trend, and, because of that, it might be appropriate to choose different management policies depending on the optimization target. It is also important to never forget about the sequential execution, as it can be more advantageous than any parallel execution in some scenarios. Overall, the execution with TM has a better performance when compared to the sequential execution in two thirds of the analysed situations, and a better EDP in one third of the scenarios. Through the analysis made in this work, it was possible to derive a minimal set of TM management policies that were able to deliver the best results with the benchmarks analysed. It was also possible to identify behavioural trends on the TM systems in certain sets of benchmarks when changing the number of cores in the execution and the workload size / Mestrado / Ciência da Computação / Mestre em Ciência da Computação

Performance objectives are often neglected during the design phase of a project, and performance problems are often not discovered until the system is implemented. Therefore, there is a need from the industry to find a method to predict the performance of a system early in the design phase. One method that tries to solve this problem is the Software Performance Engineering (SPE) method. This report gives a short introduction to software performance and an overview of the SPE method for performance prediction. It also contains a case study where SPE is applied on an existing system.

Java Performance Measurement Framework (JPMF) is a framework dedicated to description of points, where the performance is measured. This description is used to gather performance data in these running points. Data are gathered and written without any processing. The handling increases bandwidth and puts high load on the storage. JPMF does not provide any possibility for user to reduce this data. This thesis aims to solve the described problem by introduction of filtering and aggregation, that should reduce the bandwidth. Additionally, performance bottlenecks in various parts of JPMF are investigated and removed. Powered by TCPDF (www.tcpdf.org)

Background: With the increase in automating the performance testing strategies, many efforts have been made to detect the Software Performance Antipatterns (SPAs). These performance antipatterns have become a major threat to software platforms at the enterprise level, and detecting these anomalies is essential in any company dealing with performance-sensitive software as these processes should be performed quite often. Due to the complexity of the process, the manual identification of performance issues has become challenging and time-consuming. Objectives: The thesis aims to address and solve the issues mentioned above by developing a tool that automatically Characterizes and Detects Software Performance Antipatterns. The goal is to automate the parameterization process of the existing approach that helps characterize SPAs and improve the interpretation of detection of SPAs. These two processes are integrated into the tool designed to be deployed in the CI/CD pipeline. The developed tool is named Chanterelle. Methods: A case study and a survey has been used in this research. A case study has been conducted at Ericsson. A similar process as in the existing approach has been automated using python. A literature review is conducted to identify an appropriate approach to improve the interpretation of the detection of SPAs. A static user validation has been conducted with the help of a survey consisting of Chanterelle feasibility and usability questions. The responses are provided by Ericsson staff (developers and tester in the field of Software performance) after the tool is presented. Results: The results indicate that the automated parameterization and detection process proposed in this thesis have a considerable execution time compared to the existing approaches and helps the developers interpret the detection results easily. Moreover, it does not include domain experts t run the tests. The results of the static user validation show that Chanterelle is feasible and usable as a tool to be used by the developers. Conclusions: The validation of the tool suggests that Chanterelle helps the developers to interpret the performance-related bugs easily. It performs the automated parameterization and detection process in a considerable time when compared with the existing approaches.

Background: Many organizations lack the time, resources, or experience to derive a myriad of input factors impacting performance. Instead, developers use the trial and error approach to analyze the performance. The trial and error approach is difficult and time taking process when working with complex systems. Many factors impact the performance of real-time software systems. But the most important factors which impact the performance of the real-time software systems are identified in this research paper. Black box (performance) testing focuses solely on the outputs generated in response to the factors supplied while neglecting the internal components of the software. Objectives: The objective of this research is to identify the most important factors which impact the performance of real-time software systems. Identifying these factors helps developers in improving the performance of real-time software systems. The context in which the objective is achieved is an Online charging system, which is one of the software in Business support systems. In context, real-time systems, the traffic changes in a fraction of seconds, so it is important measuring the performance of these systems. Latency is also one of the major factors which impact the performance of any real-time system. Additionally, another motivation for this research is to explore a few other major factors which impact the performance. Methods: Systematic Mapping Study (SMS) and case study were conducted to identify the important factors which impact the performance of real-time software systems. Both the data collection methods, a survey and interviews were designed and executed to collect the qualitative data. Survey and interviews were conducted among 12 experienced experts who have prior knowledge regarding the performance of the system to know the most important factors that impact the performance of the online charging system. The qualitative data collected from the case study are categorized by using thematic analysis. From the logs, i.e., quantitative data collected from industry was analyzed by using random forest feature importance algorithm to identify the factors which have the highest impact on the performance of the online charging system. Results: Systematic mapping study was conducted in the literature to review the existing literature; 22 factors are identified from 21 articles. 12 new factors are identified from the survey, which was previously not identified in the literature study. From the available quantitative data based on the performance impact of the factors on the system, the factors are identified. Knowing these factors helps the developers to resolve the performance issues by allocating more number of virtual machines, thereby the performance of the system can be improved and also the behaviour of the system can be known. All these results are purely based on the expert's opinions. Conclusions: This study identifies the most important factors that impact the performance of real-time software systems. The identified factors are mostly technical factors such as CPU utilization, Memory, Latency, etc.. The objectives are addressed by selecting suitable research methods.

Application Performance Monitoring (APM) används i allt större utsträckning för att samla in data om mjukvarusystems prestanda och om hur användare interagerar med systemen. Detta för att säkerställa tillgänglighet och robusthet samt förbättra slutanvändarupplevelser. Syftet med denna studie är att undersöka hur införandet av APM kan gå till, vilka utmaningar som finns samt vilka kostnader och prestandaförsämringar som införandet innebär. Detta görs genom en fallstudie där APM implementeras i Enterprise Resource Planning-systemet MONITOR G5 som utvecklats av det svenska företaget Monitor ERP System AB. Systemet är utvecklat i Microsofts mjukvaruramverk .NET Framework och APM-tjänsten som används är Microsofts Application Insights. Studien resulterade i ett förslag på en APM-lösning där data om användarinteraktioner, prestanda och uppkomna fel samlas in och visualiseras. Sex instrumentpaneler skapades som visar olika aspekter av insamlade data, bland annat prestandamätvärden såsom processor- och minnesanvändning, uppkomna fel, laddningstider för vyer samt vilka delar av systemet som används mest och minst. Kostnadsanalysen visar att kostnaderna kan bli väldigt höga, men förslag på strategier för att hålla kostnaderna nere ges. Prestandatesterna som utfördes för att undersöka APM-lösningens påverkan på systemets prestanda gav otillförlitliga resultat, men det är troligt att prestandakostnaden för APM är liten. / The use of Application Performance Monitoring (APM) for collecting data about performance and end-user behaviors in complex software systems is increasing. APM is used to ensure availability and robustness and to enhance end-user experiences. This study aims to investigate how the adoption of APM can be done, what challenges organizations face during the implementation as well as costs and performance overhead associated with APM. This is achieved through a case study in which APM is introduced into the Enterprise Resource Planning (ERP) system MONITOR G5, developed and maintained by the Swedish software company Monitor ERP System AB. The system is developed in Microsoft’s .NET Framework and the APM service used is Microsoft’s Application Insights. The study resulted in a proposed APM solution wherein data regarding user interactions, performance and errors are collected and visualized. Six dashboards were created, showing different aspects of the collected data, for instance: which parts of the system is most and least frequently used, errors, load times and performance metrics such as processor and memory usage. The cost analysis shows that monetary costs can be very high, but strategies for suppressing costs are proposed. The performance tests that were conducted to determine the performance overhead of APM are inconclusive, but it is likely that the performance penalty of using APM is small.