1,721,003 research outputs found
Steps towards the automatic production of performance models of web applications
No full textThe automatic production of performance models of software products can encourage software designers to include performance validation in their best practices. The incorporation of methods for automatic production can also be of interest of CASE tool vendors to improve the capabilities of their commercial software development environments. This paper deals with a method that introduces a systematic approach towards the automatic production of performance models of web applications (i.e. software applications run on web platforms). The method takes in input two sets of data, the description of the platform architecture (a general view of the system platform and a detailed view of the packet flow in the platform itself) and a set of data that describes the workload imposed on the platform by the application. The produced model is an extended queueing network ready to be used by conventional evaluation tools to derive predictions on the performance of the software applications. An example is given of the method application, in which predictions of the performance of the application are obtained versus various combinations of the processing powers of the interacting hosts
Design of XMI-based tools for building EQN models of software systems
No full textResearch in software development is proving that model building during product development is essential to product validation. Indeed the model can be used in the early stages of the product lifecycle to predict the product compliance with the user performance requirements. This paper deals with software performance model building. Only a few methods and tools have been introduced for performance model automatic building, which would be of great interest to software developers, since existing performance methods and tools require a deep knowledge of performance theory. This paper illustrates the design of a tool for automatically building software performance models. The produced model is a queueing network. The design is based on recently published standards like MOF and XMI, that facilitate the easy interchange of models between different tools (e.g., software development tools, evaluation tools, etc.)
A software architecture to ease the development of distributed simulation systems
No full textThe simulation of modern systems may require an amount of computational resources that might not be available on a single host. Distributed simulation (DS) provides an effective way to scale up for the increased computational requirements. However, using existing DS environments remains the main obstacle to the wide adoption of DS systems, because of their inherent complexity. This complexity can be quantitatively shown by the extra effort that the development of DS systems requires compared to the development of conventional local simulation (LS) systems. In this paper we introduce SimArch, a layered architecture that eases the development of DS systems by enabling simulation developers to effortlessly obtain a DS system or derive a DS system from the equivalent LS one. A reference model is used throughout the paper to illustrate the use of SimArch in the development of DS systems and to prove how the DS development effort is lowered down with respect to the use of a conventional DS environment
Aggregation and Disaggregation in Queueing Networks: the Principle of Product-Form Synthesis
No full textA critical view of exact aggregation as a means of performing parametric analysis of queueing networks is introduced. The use of the so-called 'reduced network' to obtain computational savings is shown to be unnecessary; exact aggregation is, however, proved to be a very powerful tool for making hierarchical system design (i. e. system synthesis) analytically possible. The concept of model 'disaggregation process' is then introduced and the sufficient conditions for its feasibility are given, with a computationally efficient disaggregation procedure
Metadata-driven design of integrated environments for software performance validation
No full textLifecycle validation of the performance of software products (i.e., the prediction of the product ability to satisfy the user performance requirements) encompasses the production of performance models from CASE documents.
The model production activity is a critical, time-consuming and error-prone activity so that lifecycle validation is still not widely accepted and applied. The reason is twofold: the lack of methods for the automatic derivation of software performance models from CASE documents and the lack of environments that implement and integrate such methods.
A number of methods for the automatic derivation of software performance models from CASE documents has been already proposed in literature, without however solving the automation problem. This paper instead faces up to such problem, by introducing an integrated and standards-based environment for the automatic derivation and evaluation of queueing-based performance models.
The environment is based on the use of standards for metadata exchange (MOF, XMI), to ease the integration of the most common UML-based CASE tools, thus enabling software designers to smoothly introduce performance validation activities into their best development practices
Performance model building of pervasive computing
No full textPerformance model building is essential to predict the ability of an application to satisfy given levels of performance or to support the search for viable alternatives. Using automated methods of model building is becoming of increasing interest to software developers who have neither the skills nor the time to do it manually. This is particularly relevant in pervasive computing, where the large number of software and hardware components requires models of so large a size that using traditional manual methods of model building would be error prone and time consuming. This paper deals with an automated method to build performance models of pervasive computing applications, which require the integration of multiple technologies, including software layers, hardware platforms and wired/wireless networks. The considered performance models are of extended queueing network (EQN) type. The method is based on a procedure that receives as input the UML model of the application to yield as output the complete EQN model, which can then be evaluated by use of any evaluation tool
Software technologies for the interoperability, reusability and adaptability of distributed simulators
No full textGiving interoperability and reusability capabilities to distributed simulators is fundamental to the widespread use of distributed simulation. The HLA standard has introduced considerable improvements with respect to previous standards, though it suffers from shortcomings such as (1) lack of interoperability among different IEEE-compliant implementations, (2) no support to the adaptation and integration of individual federates and (3) poor reusability, which is limited to entire federates only. In this paper, we present two independent technologies that overcome such shortcomings. The first technology consists of a CORBA-HLA architecture that overcomes limitation (1), the second technology is a new development framework called SimJ that overcomes limitations (2) and (3). The CORBA-HLA architecture decouples federates from the specific HLA implementation so that federates can be effortlessly run on top of any HLA implementation that exposes services through an IEEE-complaint IDL interface. The SimJ framework eases the development of individual federates by providing a uniform and standard interface for local and distributed simulators, and makes it possible the reuse of components smaller than entire federates in both local and distributed simulators
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