Automatic code generation and tuning for stencil kernels on modern shared memory architectures

In this paper, we present Patus, a code generation and auto-tuning framework for stencil computations targeted at multi- and manycore processors, such as multicore CPUs and graphics processing units. Patus, which stands for "Parallel Autotuned Stencils,” generates a compute kernel from a specification of the stencil operation and a strategy which describes the parallelization and optimization to be applied, and leverages the autotuning methodology to optimize strategy-specific parameters for the given hardware architectur

Facilitating the Reactive Web - A Condition Action System using Node.js

The orchestration of the Web is a big issue for Web users all around the world. Web users have a high interest in services, which are able to personalise and customise the Web. However, for Web reactivity there exists only a few limited solutions that allow the aggregation of Web resources. This paper takes a look at existing event- based methods that build upon Event-Condition-Action (ECA) Rules and Complex Event Processing (CEP). Moreover, this paper illustrates the architecture of a fully functioning Condition Action System prototype for the creation of reactivity in between Web resources. In a proof of concept, we could detect and determine the change interval of electronic newspaper headlines. With the proposed system, we are able to orchestrate Web resources e.g. Detecting Web Changes. The orchestration of the Web is a big issue for Web users all around the world. Web users have a high interestin services, which are able to personalise and customise the Web. However, for Web reactivity there exists onlya few limited solutions that allow the aggregation of Web resources. This paper takes a look at existing event-based methods that build upon Event-Condition-Action (ECA) Rules and Complex Event Processing (CEP).Moreover, this paper illustrates the architecture of a fully functioning Condition Action System prototype forthe creation of reactivity in between Web resources. In a proof of concept, we could detect and determine thechange interval of electronic newspaper headlines. With the proposed system, we are able to orchestrate Webresources e.g. Detecting Web Changes

Web-based test and assessment system : design principles and case study

Courseware engineering targets towards the cost-efficient production and maintenance of educational material. We propose a separation of courseware into content parts, presentation parts, and pedagogic and didactic parts as a major step in order to strengthen reusability and adaptability of e-learning contents. This separation should guarantee that specialists can focus on their field and define questions without concerning about presentation or design the look and feel without going into details of the question content. As a case study, we present tetrodo, a framework for web-based education and show its application for the development of test and assessment purposes. Our system supports computer-correctable questions at higher taxonomy levels compared to the multiple-choice and fill-in type supported by commercial e-learning systems. In order to show a flavour what is possible, we give examples from a recent course on Algorithms and Data Structures. We sketch the hierarchy of question patterns built up and report on the authoring tool developed. Finally we describe a new approach in students involvement in questioning and summarize practical experiences so far

Performance modeling for parallel skeletons: the ALPSTONE Project

The ALPSTONE Project defines means to predict a parallel program's performance. After a short overview of ALPSTONE, we explain the modeling method and sketch the software environment used for this purpose. 1 Introduction Because it is time-consuming to write parallel programs, late performance analysis is inacceptable due to the costs of a possible redesign. Thus, when developing parallel programs, it is necessary to analyze program performance very early in the engineering process. Preferrably, one gives a specification of the problem, gets a performance prediction and either redesigns the algorithm or programs all details. To minimize development efforts, several projects (cf. [1]) at the Basel Parallel Processing Lab have been developed with the focus on skeleton oriented programming. A common base defining the vocabulary, called BACS 1 , has been developed and enhanced for the ALPSTONE Project. The methodology and tools used in ALPSTONE define a road map that guides a programme..

Reproducible experiments in parallel computing: concepts and stencil compiler benchmark study

For decades, the majority of the experiments on parallel computers have been reported at conferences and in journals usually without the possibility to verify the results presented. Thus, one of the major principles of science, reproducible results as a kind of correctness proof, has been neglected in the field of experimental high-performance computing. While this is still the state-of-the-art, current research targets for solutions to this problem. We discuss early results regarding reproducibility from a benchmark case study we did. In our experiments we explore the class of stencil calculations that are part of many scientific kernels and compare the performance results of four stencil compilers. In order to make these experiments reproducible from remote, a first prototype of an replication engine has been developed that can be accessed via the internet