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  • 1.
    Alexeeva, Zoya
    et al.
    ABB Corporate Research, Germany.
    Perez-Palacin, Diego
    Politecnico di Milano, Italy.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Design Decision Documentation: A Literature Overview2016In: Software Architecture: 10th European Conference, ECSA 2016, Copenhagen, Denmark, November 28 -- December 2, 2016, Proceedings / [ed] Bedir Tekinerdogan, Uwe Zdun, Ali Babar, Springer, 2016, p. 84-101Conference paper (Refereed)
    Abstract [en]

    Despite the abundance of research on methodologies for the documentation of design decisions and the evidence linking documentation to the improvement in the systems evolution, their practical adoption seems to be sparse. To understand this issue, we have conducted an overview of state-of-the-art on documentation of design decisions. We pursue an identification of characteristics of the different techniques proposed in the literature, such as the final goal of the documentation, the quantity of information attached to each decision documentation, the rigour of the proposed technique or its level of automation. To unveil these, we propose six classification dimensions, relevant for the industrial application, and use them to structure and analyse the review results. This work contributes with a taxonomy of the area, a structured overview covering 96 publications and a summary of open questions, which can be addressed by future research to facilitate practical adoption.

  • 2.
    Ardagna, Danilo
    et al.
    Politecnico di Milano, Italy.
    Bernardi, Simona
    University Center for Defense, Spain.
    Gianniti, Eugenio
    Politecnico di Milano, Italy.
    Aliabadi, Soroush Karimian
    Sharif University of Technology, Iran.
    Perez-Palacin, Diego
    Politecnico di Milano, Italy.
    Requeno, José Ignacio
    University of Zaragoza, Spain.
    Modeling performance of Hadoop applications: A journey from queueing networks to stochastic well formed nets2016In: Algorithms and Architectures for Parallel Processing: 16th International Conference, ICA3PP 2016, Granada, Spain, December 14-16, 2016, Proceedings / [ed] Jesus Carretero, Javier Garcia-Blas, Ryan K.L. Ko, Peter Mueller, Koji Nakano, Springer, 2016, p. 599-613Conference paper (Refereed)
    Abstract [en]

    Nowadays, many enterprises commit to the extraction of actionable knowledge from huge datasets as part of their core business activities. Applications belong to very different domains such as fraud detection or one-to-one marketing, and encompass business analytics and support to decision making in both private and public sectors. In these scenarios, a central place is held by the MapReduce framework and in particular its open source implementation, Apache Hadoop. In such environments, new challenges arise in the area of jobs performance prediction, with the needs to provide Service Level Agreement guarantees to the end-user and to avoid waste of computational resources. In this paper we provide performance analysis models to estimate MapReduce job execution times in Hadoop clusters governed by the YARN Capacity Scheduler. We propose models of increasing complexity and accuracy, ranging from queueing networks to stochastic well formed nets, able to estimate job performance under a number of scenarios of interest, including also unreliable resources. The accuracy of our models is evaluated by considering the TPC-DS industry benchmark running experiments on Amazon EC2 and the CINECA Italian supercomputing center. The results have shown that the average accuracy we can achieve is in the range 9–14%.

  • 3.
    Artac, Matej
    et al.
    XLAB, Slovenia.
    Borovsak, Tadej
    XLAB, Slovenia.
    Di Nitto, Elisabetta
    The Polytechnic University of Milan, Italy.
    Guerriero, Michele
    The Polytechnic University of Milan, Italy.
    Perez-Palacin, Diego
    Linnaeus University, Faculty of Technology, Department of computer science and media technology (CM).
    Tamburri, Damian Andrew
    The Polytechnic University of Milan, Italy.
    Infrastructure-as-code for data-intensive architectures: a model-driven development approach2018In: 2018 IEEE 25th International Conference on Software Architecture (ICSA), IEEE, 2018, p. 156-165Conference paper (Refereed)
    Abstract [en]

    As part of the DevOps tactics, Infrastructure-as- Code (IaC) provides the ability to create, configure, and manage complex infrastructures by means of executable code. Writing IaC, however, is not an easy task, since it requires blending different infrastructure programming languages and abstractions, each specialized on a particular aspect of infrastructure creation, configuration, and management. Moreover, the more the architectures become large and complex (e.g. Data-Intensive or Microservice-based architectures), the more dire the need of IaC becomes. The goal of this paper is to exploit Model- Driven Engineering (MDE) to create language-agnostic models that are then automatically transformed into IaC. We focus on the domain of Data-Intensive Applications as these typically exploit complex infrastructures which demand sophisticated and fine-grained configuration and re-configuration — we show that, through our approach, called DICER, it is possible to create complex IaC with significant amounts of time savings, both in IaC design as well as deployment and re-deployment times.

  • 4.
    Bernardi, Simona
    et al.
    University of Zaragoza, Spain.
    Domínguez, Juan L.
    Prodevelop SL, Spain.
    Gómez, Abel
    Universitat Oberta de Catalunya, Spain.
    Joubert, Christophe
    Prodevelop SL, Spain.
    Merseguer, Jose
    University of Zaragoza, Spain.
    Perez-Palacin, Diego
    Linnaeus University, Faculty of Technology, Department of computer science and media technology (CM).
    Requeno, José I.
    University of Zaragoza, Spain.
    Romeu, Alberto
    Prodevelop SL, Spain.
    A systematic approach for performance assessment using process mining: An industrial experience report2018In: Journal of Empirical Software Engineering, ISSN 1382-3256, E-ISSN 1573-7616, Vol. 23, no 6, p. 3394-3441Article in journal (Refereed)
    Abstract [en]

    Software performance engineering is a mature field that offers methods to assess system performance. Process mining is a promising research field applied to gain insight on system processes. The interplay of these two fields opens promising applications in the industry. In this work, we report our experience applying a methodology, based on process mining techniques, for the performance assessment of a commercial data-intensive software application. The methodology has successfully assessed the scalability of future versions of this system. Moreover, it has identified bottlenecks components and replication needs for fulfilling business rules. The system, an integrated port operations management system, has been developed by Prodevelop, a medium-sized software enterprise with high expertise in geospatial technologies. The performance assessment has been carried out by a team composed by practitioners and researchers. Finally, the paper offers a deep discussion on the lessons learned during the experience, that will be useful for practitioners to adopt the methodology and for researcher to find new routes.

  • 5.
    Garcia-Valls, Marisol
    et al.
    Univ Carlos III Madrid, Spain.
    Perez-Palacin, Diego
    Linnaeus University, Faculty of Technology, Department of computer science and media technology (CM).
    Mirandola, Raffaela
    Politecn Milan, Italy.
    Pragmatic cyber physical systems design based on parametric models2018In: Journal of Systems and Software, ISSN 0164-1212, E-ISSN 1873-1228, Vol. 144, p. 559-572Article in journal (Refereed)
    Abstract [en]

    The adaptive nature of cyber physical systems (CPS) comes from the fact that they are deeply immersed in the physical environments that are inherently dynamic. CPS also have stringent requirements on real-time operation and safety that are fulfilled by rigorous model design and verification. In the real-time literature, adaptation is mostly limited to off-line modeling of well known and predicted transitions; but this is not appropriate for cyber physical systems as each transition can have unique and unknown characteristics. In the adaptive systems literature, adaptation solutions are silent about timely execution and about the underlying hardware possibilities that can potentially speed up execution. This paper presents a solution for designing adaptive cyber physical systems by using parametric models that are verified during the system execution (i.e., online), so that adaptation decisions are made based on the timing requirements of each particular adaptation event. Our approach allows the system to undergo timely adaptations that exploit the potential parallelism of the software and its execution over multicore processors. We exemplify the approach on a specific use case with autonomous vehicles communication, showing its applicability for situations that require time-bounded online adaptations.

  • 6.
    García-Valls, Marisol
    et al.
    University Carlos III, Spain.
    Perez-Palacin, Diego
    Politecnico di Milano, Italy.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Extending the verification capabilities of middleware for reliable distributed self-adaptive systems2014In: 12th IEEE International Conference on Industrial Informatics (INDIN), IEEE, 2014, p. 164-169Conference paper (Refereed)
    Abstract [en]

    The design of the embedded software for industrial systems progressively integrates more intelligent functions to ease the integration between the factory floor hardware and operator-friendly control front ends. New software development paradigms such as service oriented architecture (SOA) make it possible by embedding small footprint web servers inside small embedded devices that are connected to the actuators which they control. In general, the timing requirements of such distributed systems are not in the front plane and temporal guarantees provided by most solutions are typically best effort. iLAND is an example of a middleware that supports communication and reconfiguration of distributed services, ensuring temporal correctness. It includes the logic for adapting the architectural structure of a service-based application (i.e., number and connections of the software pieces/functions) to respond to operator requests in a time-deterministic way, focusing only on the temporal correctness. In this paper, we apply the principles of autonomic computing to the middleware design, and we provide a high-level description on how its verification process could be extended beyond the purely temporal properties using more comprehensive formal techniques. We exemplify these ideas with a modified on-line verification manager that suits the needs of a kind of systems with specific timing and functional constraints.

  • 7.
    García-Valls, Marisol
    et al.
    University Carlos III, Spain.
    Perez-Palacin, Diego
    Politecnico di Milano, Italy.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Time-Sensitive Adaptation in CPS through Run-Time Configuration Generation and Verification2014In: Proceedings of the 2014 IEEE 38th Annual Computer Software and Applications Conference, IEEE Press, 2014, p. 332-337Conference paper (Refereed)
    Abstract [en]

    The inherent dynamic nature of Cyber Physical Systems (CPS) requires novel mechanisms to support their evolution over their operation life time. Though typically the development of CPS integrates the software (cyber) design with the physical domain, this contribution concentrates mainly on another essential integration plane: The software design level. This paper presents an approach to support the adaptation process of CPS required by their evolution. It is based on the run-time generation of verified system configurations and their analysis to guide the evolution of the system through correct configurations that meet the functional and timing requirements of the new situations. We show its feasibility by presenting and analyzing the results of the execution for a reduced-scale time-sensitive application that employs a complex verification technique to model functional and temporal aspects of the system.

  • 8.
    Mirandola, Raffaela
    et al.
    Politecnico di Milano, Italy.
    Perez-Palacin, Diego
    Politecnico di Milano, Italy.
    Software QoS Enhancement through Self-adaptation and Formal Models2014In: Proceedings of the 10th international ACM Sigsoft conference on Quality of software architectures, New York, USA: ACM Press, 2014, p. 145-146Conference paper (Refereed)
    Abstract [en]

    Modern software operates in highly dynamic and often unpredictable environments that can degrade its quality of service. Therefore, it is increasingly important having systems able to adapt their behavior to the environment where they execute at any moment. Nevertheless, software with self-adaptive capabilities is difficult to develop. To make easier its development, different architectural frameworks have been proposed during the last years. A shared characteristic among most frameworks is that they define applications that make an internal use of models, which are analyzed to discover the configurations that better fit in the changing environments.

    In this context, this tutorial presents the current research advances on architectural frameworks for building self-adaptive software that meets its Quality of Service (QoS). We discuss architectures that use self-adaption to improve the QoS and whose adaptations are planned as a result of the analysis of formal models. We also describe a set of current research challenges that are still preventing the complete automatic control of dependable self-adaptive software.

  • 9.
    Mirandola, Raffaela
    et al.
    Politecnico di Milano, Italy.
    Perez-Palacin, Diego
    Politecnico di Milano, Italy.
    Scandurra, Patrizia
    Università degli Studi di Bergamo, Italy.
    Brignoli, Michele
    Università degli Studi di Bergamo, Italy.
    Zonca, Andrea
    Università degli Studi di Bergamo, Italy.
    Business Process Adaptability Metrics for QoS-Based Service Compositions2015In: Service Oriented and Cloud Computing, Springer, 2015, p. 110-124Conference paper (Refereed)
    Abstract [en]

    Modern service-oriented software applications, like those envisioned in cloud computing scenarios, operate in highly dynamic and often unpredictable environments that can degrade their quality of service. Therefore, it is increasingly important to efficiently and effectively manage the adaptation of such service compositions while guaranteeing quality attributes, such as availability, performance or cost. Within this context, software metrics to quantify the adaptability of a business process in orchestrating distributed services are highly demanded in conjunction with techniques for evaluating other system quality attributes. This paper proposes a set of software metrics to quantify the adaptability of a service-oriented application when services are composed dynamically trough a business process. The paper also proposes an approach for analyzing tradeoffs between the application adaptability and a quality of service such as availability. The feasibility of the approach is illustrated through a case study carried out with a tool we have developed.

  • 10.
    Pagliari, Lorenzo
    et al.
    Politecnico di Milano, Italy.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Perez-Palacin, Diego
    Politecnico di Milano, Italy.
    Trubiani, Catia
    Gran Sasso Science Institute, Italy.
    Energy-aware adaptive techniques for information diffusion in ungoverned peer-to-peer networks2016In: Proceedings : 2016 12th International ACM SIGSOFT Conference on Quality of Software Architectures: QoSA 2016 : 5–8 April 2016, Venice, Italy, IEEE Press, 2016, p. 96-105Conference paper (Refereed)
    Abstract [en]

    The problem of handling emergency situations (e.g., earthquakes, tornados, hurricanes, political rebellions, etc.) is very challenging since the fixed network infrastructures can become unusable, and it is fundamental to build a peer-to-peer network intended to spread information among people involved in the emergency. The goal of this paper is to propose an approach that enables an adaptive behavior of ungoverned communication networks with the purpose of maximizing the information diffusion and minimizing the energy consumption of the communication devices (e.g., smartphones). We introduce an energy-aware gossip algorithm to adapt the message passing methodology among the involved devices on the basis of their battery level, while guaranteeing the information diffusion within a certain geographical area and minimizing the overall energy consumption. The approach is implemented in a simulation context that allows to quantify the percentage of area coverage within a certain interval of time by adapting the process of message passing on the basis of devices' battery level. Experimental results demonstrate that our approach outperforms classic broadcast algorithms up to 85.58% in terms of energy consumption.

  • 11.
    Perez-Palacin, Diego
    et al.
    University of Zaragoza, Spain.
    Calinescu, Radu
    University of York, UK.
    Merseguer, Jose
    University of Zaragoza, Spain.
    Log2cloud: Log-based prediction of cost-performance trade-offs for cloud deployments2013In: Proceedings of the 28th Annual ACM Symposium on Applied Computing, ACM Press, 2013, p. 397-404Conference paper (Refereed)
    Abstract [en]

    Numerous organisations are considering moving at least some of their existing applications to the cloud. A key motivating factor for this fast-paced adoption of cloud is the expectation of cost savings. Estimating what these cost savings might be requires comparing the known cost of running an application in-house with a predicted cost of its cloud deployment. A major problem with this approach is the lack of suitable techniques for predicting the cost of the virtual machines (VMs) that a cloud-deployed application requires in order to achieve a given service-level agreement. We introduce a technique that addresses this problem by using established results from queueing network theory to predict the minimum VM cost of cloud deployments starting from existing application logs. We describe how this formal technique can be used to predict the cost-performance trade-offs available for the cloud deployment of an application, and presents a case study based on a real-world webmail service.

  • 12.
    Perez-Palacin, Diego
    et al.
    Linnaeus University, Faculty of Technology, Department of computer science and media technology (CM).
    Merseguer, Jose
    Univ Zaragoza, Spain.
    Requeno, Jose, I
    Univ Zaragoza, Spain.
    Guerriero, M.
    Politecn Milan, Italy.
    Di Nitto, Elisabetta
    Politecn Milan, Italy.
    Tamburri, D. A.
    Politecn Milan, Italy.
    A UML Profile for the Design, Quality Assessment and Deployment of Data-intensive Applications2019In: Software and Systems Modeling, ISSN 1619-1366, E-ISSN 1619-1374, Vol. 18, no 6, p. 3577-3614Article in journal (Refereed)
    Abstract [en]

    Big Data or Data-Intensive applications (DIAs) seek to mine, manipulate, extract or otherwise exploit the potential intelligence hidden behind Big Data. However, several practitioner surveys remark that DIAs potential is still untapped because of very difficult and costly design, quality assessment and continuous refinement. To address the above shortcoming, we propose the use of a UML domain-specific modeling language or profile specifically tailored to support the design, assessment and continuous deployment of DIAs. This article illustrates our DIA-specific profile and outlines its usage in the context of DIA performance engineering and deployment. For DIA performance engineering, we rely on the Apache Hadoop technology, while for DIA deployment, we leverage the TOSCA language. We conclude that the proposed profile offers a powerful language for data-intensive software and systems modeling, quality evaluation and automated deployment of DIAs on private or public clouds.

  • 13.
    Perez-Palacin, Diego
    et al.
    University of Zaragoza, Spain.
    Merseguer, José
    University of Zaragoza, Spain.
    Performance Evaluation of Self-reconfigurable Service-oriented Software With Stochastic Petri Nets2010In: Electronical Notes in Theoretical Computer Science, ISSN 1571-0661, E-ISSN 1571-0661, Vol. 261, p. 181-201Article in journal (Refereed)
    Abstract [en]

    Open-world software is a paradigm which allows to develop distributed and heterogeneous software systems. They can be built by integrating already developed third-party services, which use to declare QoS values (e.g., related to performance). It is true that these QoS values are subject to some uncertainties. Consequently, the performance of the systems using these services may unexpectedly decrease. A challenge for this kind of software is to self-adapt its behavior as a response to changes in the availability or performance of the required services. In this paper, we develop an approach to model self-renconfigurable open-world software systems with stochastic Petri nets. Moreover, we develop strategies for a system to gain a new state where it can recover its availability or even improve its performance. Through an example, we apply these strategies and evaluate them to discover suitable reconfigurations for the system. Results will announce appropriate strategies for system performance enhancement.

  • 14.
    Perez-Palacin, Diego
    et al.
    University of Zaragoza, Spain.
    Merseguer, José
    University of Zaragoza, Spain.
    Performance sensitive self-adaptive service-oriented software using hidden Markov models2011In: Proceedings of the 2nd ACM/SPEC International Conference on Performance engineering, ACM Publications, 2011, p. 201-206Conference paper (Refereed)
    Abstract [en]

    Service Oriented Architecture (SOA) is a paradigm where applications are built on services offered by third party providers. Behavior of providers evolves and makes a challenge the performance prediction of SOA applications. A proper decision about when a provider should be substituted can dramatically improve the performance of the application. We propose hidden Markov models (HMM) to help service integrators to foretell the current state of third-parties. The paper leverages different algorithms that change providers based on predictions about their states. We also integrate these algorithms and HMMs in an architectural solution to coordinate them with other challenges in the SOA world.

  • 15.
    Perez-Palacin, Diego
    et al.
    University of Zaragoza, Spain.
    Merseguer, José
    University of Zaragoza, Spain.
    Bernardi, Simona
    University of Turin, Italy.
    Performance aware open-world software in a 3-layer architecture2010In: Proceedings of the first joint WOSP/SIPEW international conference on Performance engineering, Association for Computing Machinery (ACM), 2010, p. 49-56Conference paper (Refereed)
    Abstract [en]

    Open-world software is a new paradigm that stresses the concept of software service as a pillar for building applications. Services are unceasingly deployed elsewhere in the open-world and are used on demand. Consequently, the performance of these open-world applications relies on the performance of definitely unknown third-parties. Another consequence is that performance prediction methods can no longer assume that service times for software activities are well-known all over the time. More feasible solutions defend that they should be inferred from the environment, for example monitoring current services executions. So, there is a need for new performance prediction methods, and it is likely that they have to be applied not only when developing, but also during software execution, so to learn from the environment and to adapt to it. In this paper, we build on a three layer architecture, taken from literature, to present an architectural approach for performance prediction in open-world software. Once the approach is presented, the paper focuses on the intricacies of its more challeging component, i.e., the generator of strategies to meet performance goals by selecting the best available set of services.

  • 16.
    Perez-Palacin, Diego
    et al.
    University of Zaragoza, Spain.
    Merseguer, José
    University of Zaragoza, Spain.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Analysis of bursty workload-aware self-adaptive systems2012In: Proceedings of the 3rd ACM/SPEC International Conference on Performance Engineering, Association for Computing Machinery (ACM), 2012, p. 75-83Conference paper (Refereed)
    Abstract [en]

    Software is often embedded in dynamic contexts where it is subjected to high variable, non-stable, and usually bursty workloads. A key requirement for a software system is to be able to self-react to workload changes by adapting its behavior dynamically, to ensure both the correct functionalities and the required performance. Research on fitting variable workload traces into formal models has been carried out using Markovian Modulated Poisson Processes (MMPP). These works concentrate on modeling stable workload states, but accurate modeling of transient times still deserves attention since they are critical moments for the self-adaptation. In this work, we build on research in the area of MMPP trace fitting and we propose a Petri net fine-grained model for highly variable workloads that also accounts for transient times. We analyze differences between models of adaptive software that accurately represent workload state changes and models that do not. We evaluate their performance and availability and compare the results.

  • 17.
    Perez-Palacin, Diego
    et al.
    Politecnico di Milano, Italy.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Dealing with uncertainties in the performance modelling of software systems2014In: Proceedings of the 10th International ACM SIGSOFT Conference on Quality of Software Architectures, New York, USA: ACM Press, 2014, p. 33-42Conference paper (Refereed)
    Abstract [en]

    Models play a central role in the assessment of software non-functional properties like performance and reliability. Models can be used both in the initial phases of development to support the designer decisions and at runtime to evaluate the impact of changes in the existing software. However, being abstraction, the models include per-se a certain degree of uncertainty. Nevertheless, often this aspect is neglected and models are used beyond their capabilities. Recognising the presence of uncertainties and managing them, would increase the level of trust in a given software model. In this paper we exploit a recently defined taxonomy that classifies the different types of uncertainties and we define a method that, starting from a given model, helps in recognising the existence of uncertainty, in classifying and managing it. We show the method at work on an example application considering the performance of the application as target non-functional property.

  • 18.
    Perez-Palacin, Diego
    et al.
    Politecnico di Milano, Italy.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Uncertainties in the modeling of self-adaptive systems: A taxonomy and an example of availability evaluation2014In: Proceedings of the 5th ACM/SPEC international conference on Performance engineering, ACM Press, 2014, p. 3-14Conference paper (Refereed)
    Abstract [en]

    The complexity of modern software systems has grown enormously in the past years with users always demanding for new features and better quality of service. Besides, software is often embedded in dynamic contexts, where requirements, environment assumptions, and usage profiles continuously change. As an answer to this need, it has been proposed the usage of self-adaptive systems. Self-adaptation endows a system with the capability to accommodate its execution to different contexts in order to achieve continuous satisfaction of requirements. Often, self-adaptation process also makes use of runtime model evaluations to decide the changes in the system. However, even at runtime, context information that can be managed by the system is not complete or accurate; i.e, it is still subject to some uncertainties. This work motivates the need for the consideration of the concept of uncertainty in the model-based evaluation as a primary actor, classifies the avowed uncertainties of self-adaptive systems, and illustrates examples of how different types of uncertainties are present in the modeling of system characteristics for availability requirement satisfaction.

  • 19.
    Perez-Palacin, Diego
    et al.
    Politecnico di Milano, Italy.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Calinescu, Radu
    University of York, UK.
    Synthesis of adaptation plans for cloud infrastructure with hybrid cost models2014In: Proceedings : 40th Euromicro Conference Series on Software Engineering and Advanced Applications: SEAA 2014 : 27–29 August 2014, Verona, Italy / [ed] Rick Rabiser, Richard Torkar, IEEE, 2014, p. 443-450Conference paper (Refereed)
    Abstract [en]

    We present a method and a tool for devising adaptation plans for the deployment of software applications on cloud computing infrastructure comprising a combination of reserved and "pay-as-you-go" resources. Starting from a trace log that represents the expected workload pattern of the application, we exploit queuing theory results to synthesize an adaptation plan that manages the cloud elasticity in a cost-effective way. To this end, the amount of resources to be reserved for a long period is quantified in a first activity of the method. Then, as a second activity, the number and types of pay-as-you-go resources is assessed. The adaptation plan produced for a real web server is shown to be cost effective even when the actual workload differs from that in the trace log by as much as 5 -- 20%.

  • 20.
    Perez-Palacin, Diego
    et al.
    Politecnico di Milano, Italy.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Merseguer, Jose
    University of Zaragoza, Spain.
    Accurate modeling and efficient QoS analysis of scalable adaptive systems under bursty workload2017In: Journal of Systems and Software, ISSN 0164-1212, E-ISSN 1873-1228, Vol. 130, p. 24-41Article in journal (Refereed)
    Abstract [en]

    Fulfillment of QoS requirements for systems deployed in the Internet is becoming a must. A widespread characteristic of this kind of systems is that they are usually subject to highly variable and bursty workloads. The allocation of resources to fulfill QoS requirements during the peak workloads could entail a waste of computing resources. A solution is to provide the system with self-adaptive techniques that can allocate resources only when and where they are required. We pursue the QoS evaluation of workload-aware self-adaptive systems based on stochastic models. In particular, this work proposes an accurate modeling of the workload variability and burstiness phenomena based on previous approaches that use Markov Modulated Poisson Processes. We extend these approaches in order to accurately model the variations of the workload strongly influence the QoS of the self-adaptive system. Unfortunately, this stochastic modeling may lead to a non tractable QoS analysis. Consequently, this work also develops an efficient procedure for carrying out the QoS analysis.

  • 21.
    Perez-Palacin, Diego
    et al.
    University of Zaragoza, Spain.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Merseguer, Jose
    University of Zaragoza, Spain.
    Software architecture adaptability metrics for QoS-based self-adaptation2011In: Proceedings of the joint ACM SIGSOFT conference -- QoSA and ACM SIGSOFT symposium: ISARCS on Quality of software architectures -- QoSA and architecting critical systems -- ISARCS, Association for Computing Machinery (ACM), 2011, p. 171-175Conference paper (Refereed)
    Abstract [en]

    One of the major current research trends in Software Engineering is the focus on the development of new techniques to deal efficiently with the design of systems that are able to evolve overtime and adapt to rapid changes of their requirements. However, it is still an open issue how to quantify and evaluate the adaptability of a given software system. In this paper we propose the definition of metrics able to quantify and evaluate such software adaptability at the architectural level. Besides, we define a relationship with the quality of service that the software must guarantee by means of a relation between the values of these metrics and the system quality requirements. The presented metrics can be used by the software architect to guide the system adaptation to fulfill the overall quality requirements.

  • 22.
    Perez-Palacin, Diego
    et al.
    University of Zaragoza, Spain.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Merseguer, José
    University of Zaragoza, Spain.
    Enhancing a QoS-based self-adaptive framework with energy management capabilities2011In: Proceedings of the joint ACM SIGSOFT conference -- QoSA and ACM SIGSOFT symposium: ISARCS on Quality of software architectures -- QoSA and architecting critical systems -- ISARCS, Association for Computing Machinery (ACM), 2011, p. 165-169Conference paper (Refereed)
    Abstract [en]

    The energy use is becoming a key design consideration in computing infrastructures and services. In this paper we focus on service-based applications and we propose an adaptation process that can be used to reduce power consumption. This adaptation process is materialized in an adaptation plan which fits into a software architecture specifically designed for self-adaptive systems. The adaptation plan guarantees a trade-off between energy consumption and QoS offered, while maintaining suitable revenues for the service provider. The proposed approach is based on the principle of proportional energy consumption obtained by scaling down energy for unused resources, considering both the number of servers switched on and the operating frequencies of that servers.

  • 23.
    Perez-Palacin, Diego
    et al.
    Politecnico di Milano, Italy.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Merseguer, José
    University of Zaragoza, Spain.
    On the relationships between QoS and software adaptability at the architectural level2014In: Journal of Systems and Software, ISSN 0164-1212, E-ISSN 1873-1228, Vol. 87, no 1, p. 1-17Article in journal (Refereed)
    Abstract [en]

    Modern software operates in highly dynamic and often unpredictable environments that can degrade its quality of service. Therefore, it is increasingly important having systems able to adapt their behavior. However, the achievement of software adaptability can influence other software quality attributes, such as availability, performance or cost. This paper proposes an approach for analyzing tradeoffs between the system adaptability and its quality of service. The proposed approach is based on a set of metrics that allow the system adaptability evaluation. The approach can help software architects to guide decisions on system adaptation for fulfilling system quality requirements. The application and effectiveness of the approach are illustrated through examples and a wide set of experiments carried out with a tool we have developed.

  • 24.
    Perez-Palacin, Diego
    et al.
    University of Zaragoza, Spain.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Merseguer, José
    University of Zaragoza, Spain.
    QoS and energy management with Petri nets: A self-adaptive framework2012In: Journal of Systems and Software, ISSN 0164-1212, E-ISSN 1873-1228, Vol. 85, no 12, p. 2796-2811Article in journal (Refereed)
    Abstract [en]

    Energy use is becoming a key design consideration in computing infrastructures and services. In this paper we focus on service-based applications and we propose an adaptation framework that can be used to reduce power consumption according to the observed workload. The adaptation guarantees a trade-off between energy consumption and system performance. The approach is based on the principle of proportional energy consumption obtained by scaling down energy for unused resources, considering both the number of servers switched on and their operating frequencies. Stochastic Petri nets are proposed for the modeling of the framework concerns, their analyses give results about the trade-offs. The application of the approach to a simple case study shows its usefulness and practical applicability. Finally, different types of workloads are analyzed with validation purposes.

  • 25.
    Perez-Palacin, Diego
    et al.
    University of Zaragoza, Spain.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Merseguer, José
    University of Zaragoza, Spain.
    Grassi, Vincenzo
    University of Rome Tor Vergata, Italy.
    QoS-based model driven assessment of adaptive reactive systems2010In: Proceedings : Third International Conference on Software Testing, Verification, and Validation—Workshops: ICST Workshops 2010 : 6–10 April 2010, Paris, France, IEEE, 2010, p. 299-308Conference paper (Refereed)
    Abstract [en]

    Adaptable reactive software systems continuously interact with their environment responding to external stimuli and triggering events that may be perceived by their users. Designing and maintaining such systems is a challenging task. A key issue to be faced concerns the assessment of their effectiveness, in terms of the ability to meet their required Quality of Service. This paper introduces a model driven approach to support this assessment, with a focus on performance and dependability attributes. Our approach takes advantage from an existing intermediate modeling language and introduces the necessary extensions to cope with reactive systems. The presented model driven framework exploits the idea of defining a model transformation chain that maps a design oriented model of the system to an analysis oriented model that lends itself to the application of a suitable analysis methodology. We identify some key concepts that should be present in the design model of an adaptable reactive system, and show how to devise a transformation from such a model to a target analysis models.

  • 26.
    Perez-Palacin, Diego
    et al.
    Politecnico di Milano, Italy.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Monterisi, Federico
    Politecnico di Milano, Italy.
    Montoli, Andrea
    HP, Italy.
    QoS-driven Probabilistic Runtime Evaluations of Virtual Machine Placement on Hosts2015In: Proceedings : 2015 IEEE/ACM 8th International Conference on Utility and Cloud Computing: UCC 2015 : 7-10 December 2015, Limassol, Cyprus / [ed] Ioan Raicu, Omer Rana, Rajkumar Buyya, IEEE, 2015, p. 90-94Conference paper (Refereed)
    Abstract [en]

    We tackle the cloud providers challenge of virtual machine placement when the client experienced Quality of Service (QoS) is of paramount importance and resource demand of virtual machines varies over time. To this end, this work investigates approaches that leverage measured dynamic data for placement decisions. Relying on dynamic data to guide decisions has, on the one hand, the potential to optimize hardware utilization, while, on the other hand, increases the risk on the provided QoS. In this context, we present three probabilistic methods for evaluation of host suitability to allocate new virtual machines. We also present experiments results that illustrate the differences in the outcomes of presented approaches.

  • 27.
    Perez-Palacin, Diego
    et al.
    Politecnico di Milano, Italy.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    Scoppetta, Marco
    Politecnico di Milano, Italy.
    Simulation of Techniques to Improve the Utilization of Cloud Elasticity in Workload-aware Adaptive Software2016In: Proceedings of the 7th ACM/SPEC on International Conference on Performance Engineering Companion, New York, USA: ACM Press, 2016, p. 51-56Conference paper (Refereed)
    Abstract [en]

    More and more software owners consider moving their IT infrastructure to the cloud. At present, cloud providers offer easy manners to deploy software artifacts. Therefore, the profile of cloud clients is no longer limited to computing experts. However, an appropriate configuration of the elasticity offered by cloud computing is still complicated. To help these clients, this work presents a simulator of the behavior of software services that run on the cloud and use the cloud elasticity for adapting their infrastructure in order to accommodate their workload in each moment. This work identifies techniques that are used to help mitigating at runtime the lack of predictability of workload changes. The presented simulator implements the identified techniques and allows users to execute scenarios where a combination of these techniques is enabled.

  • 28.
    Perez-Palacin, Diego
    et al.
    University of Zaragoza, Spain.
    Ridene, Youssef
    Netfective Technology, France.
    Merseguer, Jose
    University of Zaragoza, Spain.
    Quality Assessment in DevOps: Automated Analysis of a Tax Fraud Detection System2017In: Proceedings of the 8th ACM/SPEC on International Conference on Performance Engineering Companion, New York, USA: ACM Press, 2017, p. 133-138Conference paper (Refereed)
    Abstract [en]

    The paper presents an industrial application of a DevOps process for a Tax fraud detection system. In particular, we report the influence of the quality assessment during development iterations, with special focus on the fulfillment of performance requirements. We investigated how to guarantee quality requirements in a process iteration while new functionalities are added. The experience has been carried out by practitioners and academics in the context of a project for improving quality of data intensive applications.

  • 29.
    Requeno, José I.
    et al.
    University of Zaragoza, Spain.
    Merseguer, José
    University of Zaragoza, Spain.
    Bernardi, Simona
    University of Zaragoza, Spain.
    Perez-Palacin, Diego
    University of Zaragoza, Spain.
    Giotis, Giorgios
    Athens Technology Center, Greece.
    Papanikolaou, Vasilis
    Athens Technology Center, Greece.
    Quantitative Analysis of Apache Storm Applications: The NewsAsset Case Study2019In: Information Systems Frontiers, ISSN 1387-3326, E-ISSN 1572-9419, Vol. 21, no 1, p. 67-85Article in journal (Refereed)
    Abstract [en]

    The development of Information Systems today faces the era of Big Data. Large volumes of information need to be processed in real-time, for example, for Facebook or Twitter analysis. This paper addresses the redesign of NewsAsset, a commercial product that helps journalists by providing services, which analyzes millions of media items from the social network in real-time. Technologies like Apache Storm can help enormously in this context. We have quantitatively analyzed the new design of NewsAsset to assess whether the introduction of Apache Storm can meet the demanding performance requirements of this media product. Our assessment approach, guided by the Unified Modeling Language (UML), takes advantage, for performance analysis, of the software designs already used for development. In addition, we converted UML into a domain-specific modeling language (DSML) for Apache Storm, thus creating a profile for Storm. Later, we transformed said DSML into an appropriate language for performance evaluation, specifically, stochastic Petri nets. The assessment ended with a successful software design that certainly met the scalability requirements of NewsAsset.

  • 30.
    Vergori, Giuseppe
    et al.
    Politecnico di Milano, Italy.
    Tamburri, Damian A
    Politecnico di Milano, Italy.
    Perez-Palacin, Diego
    Univeristy of Zaragoza, Spain.
    Mirandola, Raffaela
    Politecnico di Milano, Italy.
    DevOps Performance Engineering: A Quasi-Ethnographical Study2017In: Proceedings of the 8th ACM/SPEC on International Conference on Performance Engineering Companion, New York, USA: ACM Press, 2017, p. 127-132Conference paper (Refereed)
    Abstract [en]

    DevOps is a software engineering strategy to reduce software changes' rollout times by adopting any set of tactics that reduce friction in software lifecycles and their organisational variables, for example: coordination, communication, product evolution, deployment, operation, continuous architecting, continuous integration and more. Going DevOps is increasingly demanding that software engineering disciplines which were typically product-oriented such as software performance engineering to rethink their typical comfort zone, enlarging their scope from product, to process or even further to ecosystem and organisational levels of abstraction. This article makes an attempt at understanding what are the dimensions in DevOps organisational scenarios that can be addressed with a performance engineering lens. To do this, we performed a quasi-ethnographical study featuring a real-life industrial DevOps scenario. Discussing our results we conclude that many synergies exist between DevOps and performance engineering each with peculiarities, limitations and challenges - more research is needed to offer a full-spectrum performance-engineering support for DevOps practitioners.

1 - 30 of 30
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