Wednesday, 13 December 2017

Session 1: Model Driven Performance and Development

Session Chair: Connie U. Smith (Performance Engineering Services)

Modeling and Simulating Flash Based Solid-State Disks for Operating Systems

Authors:

Kaoutar El Maghraoui (IBM T.J. Watson Research Center)
Gokul Kandiraju (IBM T.J. Watson Research Center)
Joefon Jann (IBM T.J. Watson Research Center)
Pratap Pattnaik (IBM T.J. Watson Research Center)

Abstract:

Solid-State Disks (SSDs) made out of Flash devices have gained a lot of prominence in recent years due to their increasing performance and endurance. A number of mechanisms are being proposed to improve the performance and reliability of these devices from technological and operating system perspectives, to integrate them into personal computers and enterprise systems. Most of such proposals are being implemented and evaluated directly on top of these SSDs and require sophisticated framework and infrastructure for thorough performance evaluation. On the other hand, to our knowledge, very little has been done on modeling Flash devices and building efficient Flash simulators that can be used to simulate SSDs. Such models and simulators can give insights to make design decisions, save a lot of cumbersome work for setup and implementation, save hardware costs and allow researchers to focus on the real methods that are being proposed.

This paper presents a linear model for NAND-based Flash devices based on the internal architecture of these devices. Parameters of the model are presented along with micro-benchmarks that can be used to extract these parameters. The model is validated on the STEC Zeus Flash SSD and extracted parameters are used to build a Flash simulator as a kernel extension in the AIX operating system. A key feature of the simulator is that it simulates I/O requests by maintaining minimal state information and is independent of the internal organization of a Flash SSD. The simulator is validated using commercial and raw-IO applications through experimentation on the simulator and real Flash disks.

DOI: 10.1145/1712605.1712611

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A Framework for Utility-Based Service Oriented Design in SASSY

Authors:

Daniel A. Menascé (George Mason University)
John M. Ewing (George Mason University)
Hassan Gomaa (George Mason University)
Sam Malek (George Mason University)
João P. Sousa (George Mason University)

Abstract:

The architecture of a software system has a significant impact on its quality of service (QoS) as measured by several performance metrics such as execution time, availability, throughput, and security. This paper presents a framework that is part of a large project called SASSY (Self-Architecting Software Systems), whose goal is to allow domain experts to specify the system requirements using a visual activity-based language. The SASSY framework automatically generates a base architecture that corresponds to the requirements. Then SASSY generates a new architecture, derived from the base architecture, that optimizes a utility function for the entire system. The utility function is a multivariate function of several QoS metrics. The paper shows a complete example and illustrates how SASSY automatically adapts to changes in the environment's QoS features.

DOI: 10.1145/1712605.1712612

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State Dependence in Performance Evaluation of Component-Based Software Systems

Authors:

Lucia Kapova (University Karlsruhe)
Babora Buhnova (Masaryk University)
Anne Martens (University Karlsruhe)
Jens Happe (Forschungszentrum Informatik (FZI))
Ralf Reussner (University Karlsruhe & Forschungszentrum Informatik)

Abstract:

Integrating rising variability of software systems in performance prediction models is crucial to allow widespread industrial use of performance prediction. One of such variabilities is the dependency of system performance on the context and history-dependent internal state of the system (or its components). The questions that rise for current prediction models are (i) how to include the state properties in a prediction model, and (ii) how to balance the expressiveness and complexity of created models.

Only a few performance prediction approaches deal with modelling states in component-based systems. Currently, there is neither a consensus in the definition, nor in the method to include the state in prediction models. For these reasons, we have conducted a state-of-the-art survey of existing approaches addressing their expressiveness to model stateful components. Based on the results, we introduce a classification scheme and present the state-defining and state-dependent model parameters. We extend the Palladio Component Model (PCM), a model-based performance prediction approach, with state-modelling capabilities, and study the performance impact of modelled state. A practical influences of the internal state on software performance is evaluated on a realistic case study.

DOI: 10.1145/1712605.1712613

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Performance Aware Open-world Software in a 3-Layer Architecture

Authors:

Diego Perez-Palacin (Universidad de Zaragoza)
José Merseguer (Universidad de Zaragoza)
Simona Bernardi (Università di Torino)

Abstract:

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.

DOI: 10.1145/1712605.1712614

Full text: PDF

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