310 research outputs found

    Dataplane Specialization for High-performance OpenFlow Software Switching

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    OpenFlow is an amazingly expressive dataplane program- ming language, but this expressiveness comes at a severe performance price as switches must do excessive packet clas- sification in the fast path. The prevalent OpenFlow software switch architecture is therefore built on flow caching, but this imposes intricate limitations on the workloads that can be supported efficiently and may even open the door to mali- cious cache overflow attacks. In this paper we argue that in- stead of enforcing the same universal flow cache semantics to all OpenFlow applications and optimize for the common case, a switch should rather automatically specialize its dat- aplane piecemeal with respect to the configured workload. We introduce ES WITCH , a novel switch architecture that uses on-the-fly template-based code generation to compile any OpenFlow pipeline into efficient machine code, which can then be readily used as fast path. We present a proof- of-concept prototype and we demonstrate on illustrative use cases that ES WITCH yields a simpler architecture, superior packet processing speed, improved latency and CPU scala- bility, and predictable performance. Our prototype can eas- ily scale beyond 100 Gbps on a single Intel blade even with complex OpenFlow pipelines

    Scalable Parallel Computers for Real-Time Signal Processing

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    We assess the state-of-the-art technology in massively parallel processors (MPPs) and their variations in different architectural platforms. Architectural and programming issues are identified in using MPPs for time-critical applications such as adaptive radar signal processing. We review the enabling technologies. These include high-performance CPU chips and system interconnects, distributed memory architectures, and various latency hiding mechanisms. We characterize the concept of scalability in three areas: resources, applications, and technology. Scalable performance attributes are analytically defined. Then we compare MPPs with symmetric multiprocessors (SMPs) and clusters of workstations (COWs). The purpose is to reveal their capabilities, limits, and effectiveness in signal processing. We evaluate the IBM SP2 at MHPCC, the Intel Paragon at SDSC, the Gray T3D at Gray Eagan Center, and the Gray T3E and ASCI TeraFLOP system proposed by Intel. On the software and programming side, we evaluate existing parallel programming environments, including the models, languages, compilers, software tools, and operating systems. Some guidelines for program parallelization are provided. We examine data-parallel, shared-variable, message-passing, and implicit programming models. Communication functions and their performance overhead are discussed. Available software tools and communication libraries are also introducedpublished_or_final_versio

    Fuzzy C-Mean And Genetic Algorithms Based Scheduling For Independent Jobs In Computational Grid

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    The concept of Grid computing is becoming the most important research area in the high performance computing. Under this concept, the jobs scheduling in Grid computing has more complicated problems to discover a diversity of available resources, select the appropriate applications and map to suitable resources. However, the major problem is the optimal job scheduling, which Grid nodes need to allocate the appropriate resources for each job. In this paper, we combine Fuzzy C-Mean and Genetic Algorithms which are popular algorithms, the Grid can be used for scheduling. Our model presents the method of the jobs classifications based mainly on Fuzzy C-Mean algorithm and mapping the jobs to the appropriate resources based mainly on Genetic algorithm. In the experiments, we used the workload historical information and put it into our simulator. We get the better result when compared to the traditional algorithms for scheduling policies. Finally, the paper also discusses approach of the jobs classifications and the optimization engine in Grid scheduling

    Analysis and Modeling of Advanced PIM Architecture Design Tradeoffs

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    A major trend in high performance computer architecture over the last two decades is the migration of memory in the form of high speed caches onto the microprocessor semiconductor die. Where temporal locality in the computation is high, caches prove very effective at hiding memory access latency and contention for communication resources. However where temporal locality is absent, caches may exhibit low hit rates resulting in poor operational efficiency. Vector computing exploiting pipelined arithmetic units and memory access address this challenge for certain forms of data access patterns, for example involving long contiguous data sets exhibiting high spatial locality. But for many advanced applications for science, technology, and national security at least some data access patterns are not consistent to the restricted forms well handled by either caches or vector processing. An important alternative is the reverse strategy; that of migrating logic in to the main memory (DRAM) and performing those operations directly on the data stored there. Processor in Memory (PIM) architecture has advanced to the point where it may fill this role and provide an important new mechanism for improving performance and efficiency of future supercomputers for a broad range of applications. One important project considering both the role of PIM in supercomputer architecture and the design of such PIM components is the Cray Cascade Project sponsored by the DARPA High Productivity Computing Program. Cascade is a Petaflops scale computer targeted for deployment at the end of the decade that merges the raw speed of an advanced custom vector architecture with the high memory bandwidth processing delivered by an innovative class of PIM architecture. The work represented here was performed under the Cascade project to explore critical design space issues that will determine the value of PIM in supercomputers and contribute to the optimization of its design. But this work also has strong relevance to hybrid systems comprising a combination of conventional microprocessors and advanced PIM based intelligent main memory

    Scalability of Distributed Engineering Computation over Cloud of Virtual Machines

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    It is investigated to verify the scalability aspects of the distributed engineering computation on the cloud computing In the study a parallel virtual machine program distributed over a network of cloud computers is used in solving a finite difference version of a typical complicated engineering differential equation It is found that there exist a pseudo-optimal number of virtual machines which does not necessarily coincide with the number of tasks and the pseudooptimal number depends on various overheads over the network of virtual machines Increasing the number of machines in the cloud beyond certain threshold one does not improve computing performance due to the communication overhead between the task processes distributed over the networ

    Performance modeling of virtual switching systems

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    International audienceVirtual switches are a key elements within the new paradigms of Software Defined Networking (SDN) and Network Function Virtualization (NFV). Unlike proprietary networking appliances, virtual switches come with a high level of flexibility in the management of their physical resources such as the number of CPU cores, their allocation to the switching function, and the capacities of the RX queues, which gives the opportunity for an efficient sizing of the system resources. We propose a model for the performance evaluation of a virtual switch. Our model resorts to servers with vacation to capture the involved interactions between queues resulting from the implemented polling strategies. The solution to the model is found using a simple fixed-point iteration and it provides estimates for customary performance metrics such as the attained throughput, the packet latency, the buffer occupancy and the packet loss rate. In the tens of explored examples, the predictions of the model were found to be accurate, thereby allowing their use for the purpose of sizing problems

    Network Function Modeling and Performance Estimation

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    This work introduces a methodology for the modelization of network functions focused on the identification of recurring execution patterns as basic building blocks and aimed at providing a platform independent representation. By mapping each modeling building block on specific hardware, the performance of the network function can be estimated in termsof maximum throughput that the network function can achieve on the specific execution platform. The approach is such that once the basic modeling building blocks have been mapped, the estimate can be computed automatically for any modeled network function. Experimental results on several sample network functions show that although our approach cannot be very accurate without taking in consideration traffic characteristics, it is very valuable for those application where even loose estimates are key. One such example is orchestration in network functions virtualization (NFV) platforms, as well as in general virtualization platforms where virtual machine placement is based also on the performanceof network services offered to them. Being able to automatically estimate the performance of a virtualized network function (VNF) on different execution hardware, enables optimal placement of VNFs themselves as well as the virtual hosts they serve, while efficiently utilizing available resources
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