Software model refactoring based on performance analysis: better working on software or performance side?

Several approaches have been introduced in the last few years to tackle the problem of interpreting model-based performance analysis results and translating them into architectural feedback. Typically the interpretation can take place by browsing either the software model or the performance model. In this paper, we compare two approaches that we have recently introduced for this goal: one based on the detection and solution of performance antipatterns, and another one based on bidirectional model transformations between software and performance models. We apply both approaches to the same example in order to illustrate the differences in the obtained performance results. Thereafter, we raise the level of abstraction and we discuss the pros and cons of working on the software side and on the performance side.Comment: In Proceedings FESCA 2013, arXiv:1302.478

Quantifying volume, velocity, and variety to support (Big) data-intensive application development

© 2017 IEEE. In the era of digital economies, data can be considered as the new commodity, fueling the next-generation software services and applications. Increasing amounts of data, generated on a daily basis by various domains, such as social networks, stock exchanges, the Internet of Things, and cyber-physical systems, are soon expected to exceed the yottabyte1 frontier. To process this overwhelming amount, Big Data solutions are being developed to enable a new generation of data-centric/data-intensive applications (DIAs) and services. However, many of such applications currently fail to meet the increasingly demanding data management requirements. In particular, proper techniques and tools to support architects and developers in DIA design are required to cope with these pressing Big Data challenges. This paper makes an initial step in this direction, aiming at reducing the gap between the architects and DIAs they have to develop. The proposed approach extends the conventional Big Data process workflow with a way of capturing and modeling the 'three Vs' of Big Data (i.e. volume, velocity, and variety) to provide useful insights on the overall process, knowing the behavior of its individual components. Starting from the V-attributes of the Big Data process components, the proposed framework provides an estimation of its V-metrics by evaluating a performance model generated from the process. To demonstrate the feasibility and the effectiveness of the approach, a case study on a computer vision DIA is reported

Analysis of a class of distributed queues with application

Recently we have developed a class of media access control algorithms for different types of Local Area Networks. A common feature of these LAN algorithms is that they represent various strategies by which the processors in the LAN can simulate the availability of a centralized packet transport facility, but whose service incorporates a particular type of change over time known as 'moving sever' overhead. First we describe the operation of moving server systems in general, for both First-Come - First-Served and Head-of-the-Line orders of service, together with an approach for their delay analysis in which we transform the moving server queueing system into a conventional queueing system having proportional waiting times. Then we describe how the various LAN algorithms may be obtained from the ideal moving server system, and how a significant component of their performance characteristics is determined by the performance characteristics of that ideal system. Finally, we evaluate the compatibility of such LAN algorithms with separable queueing network models of distributed systems by computing the interdeparture time distribution for M/M/1 in the presence of moving server overhead. Although it is not exponential, except in the limits of low server utilization or low overhead, the interdeparture time distribution is a weighted sum of exponential terms with a coefficient of variation not much smaller than unity. Thus, we conjecture that a service centre with moving server overhead could be used to represent one of these LAN algorithms in a product form queueing network model of a distributed system without introducing significant approximation errors

Modelado y simulación de performance de transacciones electrónicas comerciales

Las organizaciones de e-Business necesitan evaluar sus estrategias de negocios basadas en plataformas tecnológicas informáticas, como estimación del rendimiento. Esta línea de investigación se orienta a desarrollar una metodología de modelado para simulación de Arquitecturas de Negocios Electrónicos, con transacciones Business to Consummer (B2C), de modo de analizar dinámicamente su comportamiento y predecir resultados. Esta metodología se basa en el Modelo de Referencia de Negocios Electrónicos y divide el estudio en dos partes: una específicamente de infraestructura tecnológica y otra de negocios. Desde el enfoque tecnológico se diseñan los Modelos de Recursos y de Carga de Trabajo y desde el enfoque de negocios se plantea el Modelo Funcional. De la integración de estos modelos se obtiene el Formalismo DEVS (Discrete EVent Systems Specification) del Modelo de Arquitectura buscado. Para la ejecución de la simulación se codifica el formalismo DEVS en la herramienta DEVSJAVA. Como resultado de la simulación se obtienen métricas que indican el rendimiento de las transacciones comerciales sobre la base de la tecnología informática.Eje: Ingeniería de Software y Base de DatosRed de Universidades con Carreras en Informática (RedUNCI

Modelado y simulación de performance de transacciones electrónicas comerciales

Las organizaciones de e-Business necesitan evaluar sus estrategias de negocios basadas en plataformas tecnológicas informáticas, como estimación del rendimiento. Esta línea de investigación se orienta a desarrollar una metodología de modelado para simulación de Arquitecturas de Negocios Electrónicos, con transacciones Business to Consummer (B2C), de modo de analizar dinámicamente su comportamiento y predecir resultados. Esta metodología se basa en el Modelo de Referencia de Negocios Electrónicos y divide el estudio en dos partes: una específicamente de infraestructura tecnológica y otra de negocios. Desde el enfoque tecnológico se diseñan los Modelos de Recursos y de Carga de Trabajo y desde el enfoque de negocios se plantea el Modelo Funcional. De la integración de estos modelos se obtiene el Formalismo DEVS (Discrete EVent Systems Specification) del Modelo de Arquitectura buscado. Para la ejecución de la simulación se codifica el formalismo DEVS en la herramienta DEVSJAVA. Como resultado de la simulación se obtienen métricas que indican el rendimiento de las transacciones comerciales sobre la base de la tecnología informática.Eje: Ingeniería de Software y Base de DatosRed de Universidades con Carreras en Informática (RedUNCI

An Efficient Monte Carlo-based Probabilistic Time-Dependent Routing Calculation Targeting a Server-Side Car Navigation System

Incorporating speed probability distribution to the computation of the route planning in car navigation systems guarantees more accurate and precise responses. In this paper, we propose a novel approach for dynamically selecting the number of samples used for the Monte Carlo simulation to solve the Probabilistic Time-Dependent Routing (PTDR) problem, thus improving the computation efficiency. The proposed method is used to determine in a proactive manner the number of simulations to be done to extract the travel-time estimation for each specific request while respecting an error threshold as output quality level. The methodology requires a reduced effort on the application development side. We adopted an aspect-oriented programming language (LARA) together with a flexible dynamic autotuning library (mARGOt) respectively to instrument the code and to take tuning decisions on the number of samples improving the execution efficiency. Experimental results demonstrate that the proposed adaptive approach saves a large fraction of simulations (between 36% and 81%) with respect to a static approach while considering different traffic situations, paths and error requirements. Given the negligible runtime overhead of the proposed approach, it results in an execution-time speedup between 1.5x and 5.1x. This speedup is reflected at infrastructure-level in terms of a reduction of around 36% of the computing resources needed to support the whole navigation pipeline

Real-time Emergency Response through Performant IoT Architectures

International audienceThis paper describes the design of an Internet of Things (IoT) system for building evacuation. There are two main design decisions for such systems: i) specifying the platform on which the IoT intelligent components should be located; and ii) establishing the level of collaboration among the components. For safety-critical systems, such as evacuation, real-time performance and evacuation time are critical. The approach aims to minimize computational and evacuation delays and uses Queuing Network (QN) models. The approach was tested, by computer simulation, on a real exhibition venue in Alan Turing Building, Italy, that has 34 sets of IoT sensors and actuators. Experiments were performed that tested the effect of segmenting the physical space into different sized virtual cubes. Experiments were also conducted concerning the distribution of the software architecture. The results show that using centralized architectural pattern with a segmentation of the space into large cubes is the only practical solution