6,194 research outputs found

    Pregelix: Big(ger) Graph Analytics on A Dataflow Engine

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    There is a growing need for distributed graph processing systems that are capable of gracefully scaling to very large graph datasets. Unfortunately, this challenge has not been easily met due to the intense memory pressure imposed by process-centric, message passing designs that many graph processing systems follow. Pregelix is a new open source distributed graph processing system that is based on an iterative dataflow design that is better tuned to handle both in-memory and out-of-core workloads. As such, Pregelix offers improved performance characteristics and scaling properties over current open source systems (e.g., we have seen up to 15x speedup compared to Apache Giraph and up to 35x speedup compared to distributed GraphLab), and makes more effective use of available machine resources to support Big(ger) Graph Analytics

    WaveScript: A Case-Study in Applying a Distributed Stream-Processing Language

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    Applications that combine live data streams with embedded, parallel,and distributed processing are becoming more commonplace. WaveScriptis a domain-specific language that brings high-level, type-safe,garbage-collected programming to these domains. This is made possibleby three primary implementation techniques. First, we employ a novelevaluation strategy that uses a combination of interpretation andreification to partially evaluate programs into stream dataflowgraphs. Second, we use profile-driven compilation to enable manyoptimizations that are normally only available in the synchronous(rather than asynchronous) dataflow domain. Finally, we incorporatean extensible system for rewrite rules to capture algebraic propertiesin specific domains (such as signal processing).We have used our language to build and deploy a sensor-network for theacoustic localization of wild animals, in particular, theYellow-Bellied marmot. We evaluate WaveScript's performance on thisapplication, showing that it yields good performance on both embeddedand desktop-class machines, including distributed execution andsubstantial parallel speedups. Our language allowed us to implementthe application rapidly, while outperforming a previous Cimplementation by over 35%, using fewer than half the lines of code.We evaluate the contribution of our optimizations to this success

    Towards a portable and future-proof particle-in-cell plasma physics code

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    We present the first reported OpenCL implementation of EPOCH3D, an extensible particle-in-cell plasma physics code developed at the University of Warwick. We document the challenges and successes of this porting effort, and compare the performance of our implementation executing on a wide variety of hardware from multiple vendors. The focus of our work is on understanding the suitability of existing algorithms for future accelerator-based architectures, and identifying the changes necessary to achieve performance portability for particle-in-cell plasma physics codes. We achieve good levels of performance with limited changes to the algorithmic behaviour of the code. However, our results suggest that a fundamental change to EPOCH3D’s current accumulation step (and its dependency on atomic operations) is necessary in order to fully utilise the massive levels of parallelism supported by emerging parallel architectures

    Enabling virtual radio functions on software defined radio for future wireless networks

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    Today's wired networks have become highly flexible, thanks to the fact that an increasing number of functionalities are realized by software rather than dedicated hardware. This trend is still in its early stages for wireless networks, but it has the potential to improve the network's flexibility and resource utilization regarding both the abundant computational resources and the scarce radio spectrum resources. In this work we provide an overview of the enabling technologies for network reconfiguration, such as Network Function Virtualization, Software Defined Networking, and Software Defined Radio. We review frequently used terminology such as softwarization, virtualization, and orchestration, and how these concepts apply to wireless networks. We introduce the concept of Virtual Radio Function, and illustrate how softwarized/virtualized radio functions can be placed and initialized at runtime, allowing radio access technologies and spectrum allocation schemes to be formed dynamically. Finally we focus on embedded Software-Defined Radio as an end device, and illustrate how to realize the placement, initialization and configuration of virtual radio functions on such kind of devices

    On Designing Multicore-aware Simulators for Biological Systems

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    The stochastic simulation of biological systems is an increasingly popular technique in bioinformatics. It often is an enlightening technique, which may however result in being computational expensive. We discuss the main opportunities to speed it up on multi-core platforms, which pose new challenges for parallelisation techniques. These opportunities are developed in two general families of solutions involving both the single simulation and a bulk of independent simulations (either replicas of derived from parameter sweep). Proposed solutions are tested on the parallelisation of the CWC simulator (Calculus of Wrapped Compartments) that is carried out according to proposed solutions by way of the FastFlow programming framework making possible fast development and efficient execution on multi-cores.Comment: 19 pages + cover pag
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