Browsing by Author "Reutiman, Robert"

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    Early Experience with Mobile Computation Outsourcing
    (2010-08-25) Ramakrishnan, Siddharth; Reutiman, Robert; Iverson, Harlan; Lian, Shimin; Chandra, Abhishek; Weissman, Jon
    End-user mobile devices such as smart phones, PDAs, and tablets, offer the promise of anywhere, anytime computing and communication. Users increasingly expect their mobile device to support the same activities (and same performance) as their desktop counterparts: seamless multitasking, ubiquitous data access, social networking, game playing, and real work, while on-the-go. To support mobility, these devices are typically constrained in terms of their compute power, energy, and network bandwidth. Supporting the full-array of desired desktop applications and behavior yet retaining the flexibility of the mobile cannot always be met using local resources alone. To achieve this vision, additional resources must be easily harnessed on-demand. In this paper, we describe opportunities for mobile outsourcing using external proxy resources. We present several application scenarios and preliminary results.
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    Standing on the Shoulders of Others: Using Proxies to Opportunistically Boost Distributed Applications
    (2010-05-25) Ramakrishnan, Siddharth; Reutiman, Robert; Chandra, Abhishek; Weissman, Jon
    Distributed applications are increasingly relying on and integrating remote resources including community data sources, services, and computational platforms. The coupling of distributed resources for data-intensive applications can expose bottlenecks across highly shared pathways, e.g. the network. In this paper, we consider applications that access remote clouds for data, computation, or services, and focus on alleviating the bottlenecks that they may encounter by using middleware deployed on a proxy network. We propose a proxy network that sits between the cloud and the end-user application offering resources to mitigate bottlenecks. In particular, we show how proxies can eliminate network bottlenecks by smart routing and perform in-network computations to boost application performance. We build on existing literature to create a unique synthesis of ideas that is the proxy network. Our results obtained through experiments on PlanetLab are promising, showing substantial improvement in latency, bandwidth, and even jitter, which can benefit a wide class of data-intensive applications. Our microbenchmarks show that routing data through select proxies can accelerate network transfer by at least 25% in almost half the cases considered. Experiments using a distributed Montage workflow mapped on a WAN showed 13% end-to-end performance improvement when data was routed through a proxy network. In addition, proxies also reduced the montage output data delivery time to users on mobile devices by 65-80% through compression and data transformation.
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    Starling: Minimizing Communication Overhead in Virtualized Computing Platforms Using Decentralized Affinity-Aware Migration
    (2009-12-02) Sonnek, Jason; Greensky, James; Reutiman, Robert; Chandra, Abhishek
    Virtualization is being widely used in large-scale computing environments, such as clouds, data centers, and grids, to provide application portability and facilitate resource multiplexing while retaining application isolation. In many existing virtualized platforms, it has been found that the network bandwidth often becomes the bottleneck resource, causing both high network contention and reduced performance for communication and data-intensive applications. In this paper, we present a decentralized affinity-aware migration technique that incorporates heterogeneity and dynamism in network topology and job communication patterns to allocate virtual machines on the available physical resources. Our technique monitors network affinity between pairs of VMs and uses a distributed bartering algorithm, coupled with migration, to dynamically adjust VM placement such that communication overhead is minimized. Our experimental results running the Intel MPI benchmark and a scientific application on a 7-node Xen cluster show that we can get up to 42% improvement in the runtime of the application over a no-migration technique, while achieving up to 85% reduction in network communication cost. In addition, our technique is able to adjust to dynamic variations in communication patterns and provides both good performance and low network contention with minimal overhead. We also present a topology-aware extension to our migration algorithm that provides an additional 26-31% reduction in runtime.