检索结果-内蒙古大学图书馆

International conference on Dependable Systems and Networks Workshops (DSN-W)

作者： Haibo Mi Huaimin Wang Gang Yin Hua Cai Qi Zhou Tingtao Sun National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China Computing Platform Alibaba Cloud Computing Company Hangzhou China

It is quite a headache for developers to online detect performance problems in large-scale cloud computing systems. The behavior and the hidden connections among the huge amount of runtime request execution paths in cloud computing systems usually contain useful information for performance problem detection. In this paper, we propose an approach to rapidly diagnose the source of performance degradation in large-scale non-stop cloud computing systems. The approach first groups the user requests into categories with a fast clustering algorithm; then applies the principal components analysis to extract the primary methods; finally compares the normal and abnormal behaviors of the primary methods to localize the main cause of performance problems. We conduct extensive experiments over a real-world enterprise system providing services for the public. The results show that our approach can locate the prime causes of performance problems accurately and efficiently.

关键词： Cloud computing Principal component analysis Instruments Degradation Servers Data mining Accuracy

来源：评论

学校读者我要写书评

暂无评论

Power Optimization for GPU Programs Based on Software Prefetching

Power Optimization for GPU Programs Based on Software Prefet...

引用

IEEE International conference on Trust, Security and Privacy in Computing and Communications (TrustCom)

作者： Yisong Lin Tao Tang Guibin Wang Key Laboratory of Science and Technology for National Defence of Parallel and Distributed Processing National University of Defense and Technology Changsha China

GPUs render higher computing unit density than contemporary CPUs and thus exhibit much higher power consumption despite its higher power efficiency. The power consumption has become an important issue that impacts CPU's applications, thereby necessitating the low power optimization technology for GPUs. Software prefetching is an efficient way to alleviate the memory wall problem which overlaps the computing and memory access latencies. However, software prefetching will cause some power overhead because it increases the number and density of the instructions. Thus, we should consider the balance between the performance income and the power overhead when applying the optimization. To address this problem, in this paper we first analyze the multi-thread execution model of GPU and validate the potential space of software prefetching optimization. Then we give the software prefetching method for GPU programs to improve the performance. Aiming at two different objects: energy optimization under performance constraint and performance optimization under power constraint, we discuss the optimization methods based on software prefetching and dynamic voltage scaling technologies. The experimental results show that our method can efficiently optimize the energy consumption (performance) under the performance (power) constraint.

关键词： Prefetching Graphics processing unit Optimization Power demand Registers

来源：评论

学校读者我要写书评

暂无评论

Scheduling in mapreduce-like systems for fast completion time

Scheduling in mapreduce-like systems for fast completion tim...

引用

IEEE Annual Joint conference: INFOCOM, IEEE Computer and Communications Societies

作者： Hyunseok Chang Murali Kodialam Ramana Rao Kompella T. V. Lakshman Myungjin Lee Sarit Mukherjee Bell Laboratories USA Purdue University USA

ISBN: (纸本)9781424499199

Large-scale data processing needs of enterprises today are primarily met with distributed and parallel computing in data centers. MapReduce has emerged as an important programming model for these environments. Since today's data centers run many MapReduce jobs in parallel, it is important to find a good scheduling algorithm that can optimize the completion times of these jobs. While several recent papers focused on optimizing the scheduler, there exists very little theoretical understanding of the scheduling problem in the context of MapReduce. In this paper, we seek to address this problem by first presenting a simplified abstraction of the MapReduce scheduling problem, and then formulate the scheduling problem as an optimization *** devise various online and offline algorithms to arrive at a good ordering of jobs to minimize the overall job completion times. Since optimal solutions are hard to compute (NP-hard), we propose approximation algorithms that work within a factor of 3 of the optimal. Using simulations, we also compare our online algorithm with standard scheduling strategies such as FIFO, Shortest Job First and show that our algorithm consistently outperforms these across different job distributions.

关键词： Program processors Approximation algorithms Optimal scheduling Processor scheduling Equations Approximation methods Optimized production technology

来源：评论

学校读者我要写书评

暂无评论

Exploring parallel capabilities of an innovative numerical method for recovering image velocity vectors field

引用

MATHEMATICAL AND COMPUTER MODELLING 2010年第3-4期51卷 138-143页

作者： Francomano, E. Macaluso, C. Tortorici, A. Toscano, E. Univ Palermo Dipartimento Ingn Informat I-90128 Palermo Italy

In this paper an efficient method devoted to estimate the velocity vectors field is investigated. The method is based on a quasi-interpolant operator and involves a large amount of computation. The operations characterizing the computational scheme are ideal for parallel processing because they are local, regular and repetitive. Therefore, the spatial parallelism of the process is studied to rapidly proceed in the computation on distributed multiprocessor systems. The process has shown to be synchoronous, with good task balancing and requiring a small amount of data transfer. (C) 2009 Elsevier Ltd. All rights reserved.

关键词： image velocity vectors field Quasi-interpolant operator B-spline functions distributed multiprocessor systems

来源：评论

学校读者我要写书评

暂无评论

Identifying faults in large-scale distributed systems by filtering noisy error logs

Identifying faults in large-scale distributed systems by fil...

引用

International conference on Dependable Systems and Networks Workshops (DSN-W)

作者： Xiang Rao Huaimin Wang Dianxi Shi Zhenbang Chen Hua Cai Qi Zhou Tingtao Sun National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China Computing Platform Alibaba Cloud Computing Corporation Hangzhou China

Extracting fault features with the error logs of fault injection tests has been widely studied in the area of large scale distributed systems for decades. However, the process of extracting features is severely affected by a large amount of noisy logs. While the existing work tries to solve the problem by compressing logs in temporal and spatial views or removing the semantic redundancy between logs, they fail to consider the co-existence of other noisy faults that generate error logs instead of injected faults, for example, random hardware faults, unexpected bugs of softwares, system configuration faults or the error rank of a log severity. During a fault feature extraction process, those noisy faults generate error logs that are not related to a target fault, and will strongly mislead the resulted fault features. We call an error log that is not related to a target fault a noisy error log. To filter out noisy error logs, we present a similarity-based error log filtering method SBF, which consists of three integrated steps: (1) model error logs into time series and use haar wavelet transform to get the approximate time series; (2) divide the approximate time series into sub time series by valleys; (3) identify noisy error logs by comparing the similarity between the sub time series of target error logs and the template of noisy error logs. We apply our log filtering method in an enterprise cloud system and show its effectiveness. Compared with the existing work, we successfully filter out noisy error logs and increase the precision and the recall rate of fault feature extraction.

关键词： Time series analysis Noise measurement Feature extraction Wavelet transforms Computer crashes Complexity theory Approximation methods

来源：评论

学校读者我要写书评

暂无评论

Pipelined high precision beamforming delay calculator for ultrasound imaging

Pipelined high precision beamforming delay calculator for ul...

引用

IEEE International conference on Field-Programmable Technology (FPT)

作者： Zhanxiang Zhao Xi Jin Xin Zhang Department of Physics University of Science and Technology Hefei China Wanyi Science and Technology Company Limited Hefei China

Ultrasound Imaging is one of the most widely used medical imaging methods, and beamforming is the enabling technology of ultrasound imaging, which directly influences the image quality. The critical problem of modern ultrasound imaging system is generating high resolution images at high frame rate. To solve this problem, real-time high precision beamforming delay parameters must be generated. This paper presents the design and implementation of a pipelined high precision beamforming delay calculator for ultrasound imaging, which uses 10-stage pipelined CORDIC (Coordinate Rotation Digital Computer) processor to perform fully pipelined architecture. The presented delay calculator calculates delay parameters with high precision, which can greatly improve the image quality. And fully pipelined architecture can also provide high frame rate. The design has been synthesized for an Altera Arria-II GX FPGA with speed grade 4. A delay calculator requires about 3,238 out of 50,600 available ALUTs (6.4%), and a 64-channel dual-beam system needs 24 such delay calculator modules. The delay calculators run in parallel, and one of them can generate 300 million delay parameters per second.

关键词： Delay Calculators Ultrasonic imaging Array signal processing Transducers Imaging Field programmable gate arrays

来源：评论

学校读者我要写书评

暂无评论

CT model experimental research on cable saddle zone of extradosed bridge

CT model experimental research on cable saddle zone of extra...

引用

International conference on Consumer Electronics, Communications and Networks

作者： Cheng Haiqian Yang Ping Wuhan University of Technology Wuhan Hubei China

ISBN: (纸本)9781612844589

Most of cable saddle test and theoretical study about extradosed bridge consider that the normal force on arc wall of embedded pipe is evenly distributed. The approximate load simulation will affect the accuracy of analytical results. Referring to the typical cable saddle structure of extradosed bridge, a polyurethane model was produced for this paper. Through a series of CT scan experiment, we obtained contact interface images under two loading conditions. Interface analysis based on image processing technology can provided displacement values of key points on the contact interface. Then the displacement values were applied as loads on the corresponding ANSYS finite element model. Results show that: 1) the contact normal pressure is nearly cosine distribution instead of uniform distribution; 2) There exist stress mutations around the junction of straight line and arc if the embedded pipe adopts "straight-arc-straight" design form. 3) Construction deviation may make excessive extrusion called "end effect" between cable and the exit of embedded pipe, causing the concrete near pipe edge appear stress concentration.

关键词： Computed tomography Bridges Power cables Finite element methods Load modeling Stress Poles and towers

来源：评论

学校读者我要写书评

暂无评论

Extracting ultra-scale Lattice Boltzmann performance via hierarchical and distributed auto-tuning

Extracting ultra-scale Lattice Boltzmann performance via hie...

引用

Supercomputing conference

作者： Samuel Williams Leonid Oliker Jonathan Carter John Shalf Computational Research Division Lawrence Berkeley National Laboratory USA

We are witnessing a rapid evolution of HPC node architectures and on-chip parallelism as power and cooling constraints limit increases in microprocessor clock speeds. In this work, we demonstrate a hierarchical approach towards effectively extracting performance for a variety of emerging multicore-based supercomputing platforms. Our examined application is a structured grid-based Lattice Boltzmann computation that simulates homogeneous isotropic turbulence in magnetohydrodynamics. First, we examine sophisticated sequential auto-tuning techniques including loop transformations, virtual vectorization, and use of ISA-specific intrinsics. Next, we present a variety of parallel optimization approaches including programming model exploration (flat MPI, MPI/OpenMP, and MPI/Pthreads), as well as data and thread decomposition strategies designed to mitigate communication bottlenecks. Finally, we evaluate the impact of our hierarchical tuning techniques using a variety of problem sizes via large-scale simulations on state-of-the-art Cray XT4, Cray XE6, and IBM BlueGene/P platforms. Results show that our unique tuning approach improves performance and energy requirements by up to 3.4x using 49,152 cores, while providing a portable optimization methodology for a variety of numerical methods on forthcoming HPC systems.

关键词： Lattices Distribution functions Optimization Three dimensional displays Vectors Multicore processing Tuning

来源：评论

学校读者我要写书评

暂无评论

Coordinate strip-mining and kernel fusion to lower power consumption on GPU

Coordinate strip-mining and kernel fusion to lower power con...

引用

Design, Automation and Test in Europe conference and Exhibition

作者： Guibin Wang National Laboratory of Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha Hunan China

ISBN: (纸本)9781612842080

Although general purpose GPUs have relatively high computing capacity, they also introduce high power consumption compared with general purpose CPUs. Therefore low-power techniques targeted for GPUs will be one of the most hot topics in the future. On the other hand, in several application domains, users are unwilling to sacrifice performance to save power. In this paper, we propose an effective kernel fusion method to reduce the power consumption for GPUs without performance loss. Different from executing multiple kernels serially, the proposed method fuses several kernels into one larger kernel. Owing to the fact that most consecutive kernels in an application have data dependency and could not be fused directly, we split large kernel into multiple slices with strip-mining method, then fuse independent sliced kernels into one kernel. Based on the CUDA programming model, we propose three different kernel fusion implementations, with each one targeting for a special case. Based on the different strip-ming methods, we also propose two fusion mechanisms, which are called invariant-slice fusion and variant-slice fusion. The latter one could be better adapted to the requirements of the kernels to be fused. The experimental results validate that the proposed kernel fusion method could effectively reduce the power consumption for GPU.

关键词： Kernel Energy consumption Graphics processing unit Power demand Instruction sets Programming Optimization

来源：评论

学校读者我要写书评

暂无评论

COLOR-COMPONENT BIT ALLOCATION SCHEME FOR JPEG 2000 parallel CODEC

COLOR-COMPONENT BIT ALLOCATION SCHEME FOR JPEG 2000 PARALLEL...

引用

IEEE International conference on image processing

作者： Tonomura, Yoshihide Nakachi, Takayuki Shirai, Daisuke Fujii, Tatsuya Kiya, Hitoshi NTT Corp NTT Network Innovat Labs Tokyo 2390847 Japan Tokyo Metropolitan Univ Fac Syst Design Dept Informat & Commun Syst Engn Hachioji Tokyo 1910065 Japan

ISBN: (纸本)9781424479948

A new bit allocation scheme for JPEG 2000 systems in parallel-distributed environments is proposed. In recent years, super high-definition images are being used for not only digital cinema also alternative services e. g. real-time sports in theaters. In general, such high-definition images are divided into small segments, such as tiles or components, and compressed. However, this process leads to low coding efficiency. In contrast, our proposed scheme controls the bit allocation ratio for each color-component separately by using the quantizer properties available in the JPEG 2000 standard. Simulation results show that the proposed scheme achieves the same coding performance as the non parallel-distributed approach.

关键词： JPEG 2000 Bit allocation parallel processing Rate distortion

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：