Simplifying Layered Queuing Network Models

Islam, Farhana; Petriu, Dorina C.; Woodside, C. Murray

doi:10.1007/978-3-319-23267-6_5

Cited by 7 publications

(16 citation statements)

References 5 publications

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“…The FES construction method isolates the subnetwork and drives it with a fixed number of customers, cycling endlessly; the mean delay of a customer in the subnetwork is taken as the service time of the FES for that number of customers. This is repeated for every user population that it may experience, which does not scale well to large systems with thousands of customers [22].…”

Section: Flow Equivalent Server Methodsmentioning

confidence: 99%

“…In this thesis, processor and host are used interchangeably. Tasks and processors are servers with queues [22]. Tasks may be multi-threaded, with threads sharing a queue, and the threads are scheduled on the host by a host queueing discipline.…”

Section: Layered Queueing Network (Lqn)mentioning

confidence: 99%

“…In this theorem, any subnetwork of queues can be replaced by a single server with a state-dependent service rate. The replacement is exact in the sense that the throughput and delay at the subnetwork interface is the same for the single server [22]. The original result was obtained for a single class of customers, and it was extended to multiple classes in [25].…”

Section: Norton's Theoremmentioning

confidence: 99%

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Simplifying Layered Queueing Network Models

Islam¹

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The amount of detail to include in a performance model is usually regarded as a judgment to be made by an expert modeler and the question "how much detail is necessary?" is seldom asked and is difficult to answer. However, if a simpler model gives essentially the same performance predictions, it may be more useful than a detailed model. It may solve more quickly, for instance, and may be easier to understand. Or a model for a complex subsystem such as a database server may be usefully simplified so it can be included in larger system models. This research proposes an aggregation process for layered queuing models that reduces the number of queues (called tasks and hosts/processors, in layered models) while preserving the total execution demand and the bottleneck characteristics (the highest saturated resource(s)) of the detailed model. This thesis demonstrates how the simplification process can greatly reduce the number of tasks and processors with a very small relative error. The application of proposed simplification process is applied on a number of case studies. A Java application called "LQN model simplifier" was built that takes an LQN model as input and generates a series of simplified models after applying simplification operations to the original model.iii

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Section: Flow Equivalent Server Methodsmentioning

confidence: 99%

Section: Layered Queueing Network (Lqn)mentioning

confidence: 99%

Section: Norton's Theoremmentioning

confidence: 99%

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Simplifying Layered Queueing Network Models

Islam¹

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“…Therefore, in general it is recommended to use PMR, unless otherwise required. The benefits of having a smaller model was described in [40].…”

Section: Modifying Realization (Smr)mentioning

confidence: 99%

“…The middleware composition algorithm, presented below, composes a specialized middleware model to a number of calls of the base application model while keeping the number of newly added tasks to the minimum. This is desirable because smaller models are easier to understand by the modelers and quicker to solve by the solver [40].…”

Section: Middleware Composition Algorithmmentioning

confidence: 99%

A Flexible Framework for Modeling Middleware Completions

Adnan¹

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Middleware has a major impact on the performance of distributed software applications.To predict the performance (e.g., response time, throughput) of an application using a performance model, it is essential to capture not only the characteristics of the application, but also the platform and the middleware. Model elements, which are added to an application software model for performance analysis are known as Completions. This research proposes a unified and flexible framework, called MMLQ (Middleware Modeling for Layered Queues), for modeling middleware completions and automatically composing them into software performance models. The existing approaches have many limitations. Some of them require to build and compose models manually, others lack generality, while others use component-based modeling which creates many elements that are not essential for performance analysis and complicate the model. MMLQ overcomes the limitations of the existing approaches and can model a wide range of middleware platforms. The contributions of this thesis include identifying the commonalities and differences among different middleware platforms, modeling their features, specializing middleware models to cater to the needs of an application, calibrating the specialized models and a proposing a process to compose calibrated models with the application models. The software application models and the middleware models are all built using Layered Queuing Network Model (LQN) developed at the RADS lab of Carleton University. The MMLQ framework is validated by showing its ability to model three different categories of middleware and by comparing the predicted performance with measured performance metrics. ii iii This work is dedicated to my lovely wife Farhana, my cute son Farhaz and my beloved mother Halima Khatun vi

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Uncertainty representation in software models: a survey

et al. 2021

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This paper provides a comprehensive overview and analysis of research work on how uncertainty is currently represented in software models. The survey presents the definitions and current research status of different proposals for addressing uncertainty modeling, and introduces a classification framework that allows to compare and classify existing proposals, analyse their current status and identify new trends. In addition, we discuss possible future research directions, opportunities and challenges.A fundamental characteristic of software models is their ability to represent the relevant characteristics of the system under study, at the appropriate level of abstraction. Software models were initially conceived to design and develop general Information Technology (IT) systems, such as financial applications, enterprise databases or component-based systems, and have proven to be excellent artefacts for representing the basic structure and

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Simplifying Layered Queuing Network Models

Cited by 7 publications

References 5 publications

Simplifying Layered Queueing Network Models

Simplifying Layered Queueing Network Models

A Flexible Framework for Modeling Middleware Completions

Uncertainty representation in software models: a survey

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