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International Conference on computer and Information technology (CIT)

作者： Wei Lin DongRui Fan He Huang Nan Yuan XiaoChun Ye Chinese Academy of Sciences Beijing China Key Laboratory of Computer System and Architecture Institute of Computing Technology Chinese Academy and Sciences Beijing China

computer architectures make a dramatic turn away from improving single-processor performance towards improved parallel performance through integrating many cores in one chip. However, providing directory based coherence protocols for these platforms is too complex and expensive. As a substitute, we propose a synchronization based cache coherence solution, which uses different cache policies according to three flexible software guided scopes (exclusion, producer and consumer scopes) to solve the data-race and coherence problem. Furthermore, this protocol implements word dirty bits (only one bit per word is needed in each L1 cache line) and a special hardware synchronization manager (HSM) to support multi-writer, the write-validate policy and to eliminate the remote un-cache spinning at the ldquoflagrdquo. We evaluate Godson-T, a platform supporting this protocol, against an idealized interleaved dual tag directory based protocol on the Splash2 and two bioinformatics benchmarks. The performance of the synch-based protocol is degraded only at 3.2% on average, but the real chip area is reduced at 32% even if the overhead of HSM is included.

关键词： Protocols computer architecture Hardware Concurrent computing Costs Network-on-a-chip Coherence Tiles Information technology Helium

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Flip-Flop Selection for Transition Test Pattern Reduction Using Partial Enhanced Scan

Flip-Flop Selection for Transition Test Pattern Reduction Us...

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Pacific Rim International Symposium on Dependable computing

作者： Songwei Pei Huawei Li Xiaowei Li Chinese Academy of Sciences Beijing China Key Laboratory of Computer System and Architecture Institute of Computing Technology Chinese Academy and Sciences Beijing China

Enhanced scan delay testing approach can achieve high transition delay fault coverage by a small size of test pattern set but with significant hardware overhead. Although the implementation cost of launch on capture (LOC) approach is relatively low, the generated pattern set for testing delay faults is typically very large. In this paper, we present a novel flip-flop selection method to combine the respective advantages of the two approaches, by replacing a small number of selected regular scan cells with enhanced scan cells, thus to reduce the overall volume of transition delay test patterns effectively. Moreover, higher fault coverage can also be obtained by this approach compared to the standard LOC approach. Experimental results on larger ISCAS-89 and ITC-99 benchmark circuits using a commercial test generation tool show that the volume of test patterns can be reduced by over 70% and the transition delay fault coverage can be improved by up to 8.7%.

关键词： Flip-flops Delay Circuit testing Lab-on-a-chip Circuit faults Test pattern generators System testing Hardware Costs Timing

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Variation-Aware Scheduling for Chip Multiprocessors with Thread Level Redundancy

Variation-Aware Scheduling for Chip Multiprocessors with Thr...

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Pacific Rim International Symposium on Dependable computing

作者： Jianbo Dong Lei Zhang Yinhe Han Guihai Yan Xiaowei Li Chinese Academy of Sciences Beijing China Key Laboratory of Computer System and Architecture Institute of Computing Technology Chinese Academy and Sciences Beijing China

Thread-level redundancy in Chip Multiprocessors(TLR-CMP) is efficient for soft error tolerance. Process variation causes core-to-core (C2C) performance asymmetry across a chip, which should be taken into consideration for application scheduling. In this paper, two types of variations beyond C2C are introduced, i.e., inter-pair and intra-pair variation in TLR-CMP. Intra-pair performance asymmetry can affect the performance of applications differently. Based on the above observation, we firstly formalize the variation aware scheduling in TLR-CMP as a 0-1 programming problem,to maximize the system weighted throughput. An efficient scheduling algorithm, named IntraVarF&AppSen, is then proposed to tackle this problem, which can be proved to be optimal when the number of applications to be scheduled is equal to the number of core pairs. Simulation on a 64-core CMP shows 2.8%-4% improvement in weighted throughput when compared to prior VarF&AppIPC algorithm.

关键词： Yarn Job shop scheduling Redundancy Throughput Scheduling algorithm Cathode ray tubes computer architecture Error analysis Transistors Multiprocessing systems

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Design of New Hash Mapping Functions

Design of New Hash Mapping Functions

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International Conference on computer and Information technology (CIT)

作者： Fenglong Song Zhiyong Liu Dongrui Fan Junchao Zhang Lei Yu Nan Yuan Wei Lin Chinese Academy of Sciences Beijing China Key Laboratory of Computer System and Architecture Institute of Computing Technology Chinese Academy and Sciences Beijing China

Conflict can decrease performance of computer severely, such as bank conflicts reduce bandwidth of interleave multibank memory systems and conflict misses reduce effective on-chip capacity, and this incurs much conflict miss further. Conflicts can be avoided by a suitable address mapping scheme which maps the most frequently occurring patterns conflict-free. In this paper, we present a new XOR-based mapping scheme, called XORM, which focuses on multi-bank shared cache of on-chip many-core architecture. The XORM mapping scheme can map arbitrary bits of address to set indices and compute each set index bit as XOR of a transpositional subset of the bits in the address. Then, we analyze necessary characteristics of an address mapping scheme to avoid conflict in many-core architecture. Next, we give a case study to design optimal hash functions based on XORM scheme for skewed-associative cache. Finally, we introduce another case study, in which we illustrate how to design an XORM mapping scheme with lower implementation cost, complexity and computing latency in shared cache of chipped many-core architecture. The evaluated results show the effectiveness of XORM mapping scheme.

关键词： computer architecture Delay Bandwidth Costs Information technology Laboratories System-on-a-chip Hardware High performance computing Polynomials

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Evaluation Method of Synchronization for Shared-Memory On-Chip Many-Core Processor

Evaluation Method of Synchronization for Shared-Memory On-Ch...

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International Symposium on Parallel and Distributed Processing with Applications, ISPA

作者： Fenglong Song Zhiyong Liu Dongrui Fan He Huang Nan Yuan Lei Yu Junchao Zhang Chinese Academy of Sciences Beijing Beijing CN Key Laboratory of Computer System and Architecture Institute of Computing Technology Chinese Academy and Sciences Beijing China

On-chip many core architecture is an emerging and promising computation platform. High speed on-chip communication and abundant chipped resources are two outstanding advantages of this architecture, which provide an opportunity to implement efficient synchronization scheme. The practical execution efficiency of synchronization scheme is critical to this platform. However, there are few researches on systematic evaluation method of choice synchronization schemes for on-chip many core processors, and effect of dedicated hardware support in this context. So we focus on the evaluation method and criterion of synchronization scheme on the platform. Firstly, we present several criterions proper to on-chip many core architecture, that is, absolute overhead of synchronization operation, the transferring time between different synchronization operations, overhead caused by load imbalance, and the network congestion caused by synchronization operation. Secondly, we illustrate how to design microbenchmarks which one dedicated to evaluate a performance criterion respectively. Finally, we implement these microbenchmarks and synchronization schemes on an on-chip many core processor with shared level-two cache and AMD Opteron commercial chip multi-processor, respectively. And we analyze effect of dedicated hardware support. Results show that the most overhead of synchronization is caused by load imbalance and serialization on synchronization point. It also shows that synchronization scheme supported with dedicated hardware can improve its performance obviously for chipped many-core processor.

关键词： computer architecture Hardware Yarn Costs System-on-a-chip Concurrent computing Distributed computing Network-on-a-chip Distributed processing Application software

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Study on Fine-Grained Synchronization in Many-Core architecture

Study on Fine-Grained Synchronization in Many-Core Architect...

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ACIS International Conference on Software Engineering, Artificial Intelligence, Networking, and Parallel/Distributed computing (SNPD)

作者： Lei Yu Zhiyong Liu Dongrui Fan Fenglong Song Junchao Zhang Nan Yuan Chinese Academy of Sciences Beijing Beijing CN Key Laboratory of Computer System and Architecture Institute of Computing Technology Chinese Academy and Sciences Beijing China

The synchronization between threads has serious impact on the performance of many-core architecture. When communication is frequent, coarse-grained synchronization brings significant overhead. Thus, coarse-grained synchronization is not suitable for this situation. However, the overhead of fine-grained synchronization is still small when the communication is frequent. For the many-core architecture which supports fine-grained synchronization with on-chip storage, we propose fine-grained synchronization algorithms for scientific computation application 2-D wavefront and LU decomposition. At first, according to the memory access mode, an efficient method of data allocation is proposed. Then, way of thread partition and synchronization are discussed. Finally, we estimate the two algorithms based on Godson-T many-core architecture. The results of experiments show that the relative speedup is almost linear and the execution time is only 53.2 % of the coarse-grained synchronization. After the global barriers are eliminated, LU decomposition achieved 13.1% performance improvement. Moreover, the experiments prove that the fine-grained mechanism is able to improve the performance of processor and it has a good scalability.

关键词： Frequency synchronization computer architecture Yarn Parallel processing Distributed computing Concurrent computing Delay Programming profession Partitioning algorithms Wire

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A case study of improving at-speed testing coverage of a gigahertz microprocessor

A case study of improving at-speed testing coverage of a gig...

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IEEE International Conference on Electronics, Circuits and Systems (ICECS)

作者： Zichu Qi Hui Liu Xiangku Li Jun Xu Weiwu Hu Chinese Academy of Sciences Beijing Beijing CN Key Laboratory of Computer System and Architecture Institute of Computing Technology Chinese Academy and Sciences Beijing China

ISBN: (纸本)9781424450909;9781424450916

For a gigahertz microprocessor with multiple clock domains and a large amount of embedded RAMs (random access memory), generating at-speed testing patterns is becoming very difficult and very time-consuming. This paper presents some novel techniques to improve at-speed testing coverage with low cost. These methods are major concern about preventing X states propagation, which include avoiding capturing X states for registers, sequential bypass of macros, clock control scheme for inter-clock domains and accurate analysis of exception paths in intra-clock domains. Functional patterns are utilized to further improve the efficiency of the at-speed testing. A novel optimal flow is presented by carefully selecting these techniques. By using the flow, 90% transition fault coverage is achieved. In addition, both the number of patterns and the test time of the transition test are decreased by 15%. The total area overhead is about a few hundreds of AND cells and has little timing impact on the critical paths.

关键词： Microprocessors Clocks Test pattern generators System testing Costs Timing Automatic test pattern generation Delay Pattern analysis Laboratories

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Data Management: The Spirit to Pursuit Peak Performance on Many-Core Processor

Data Management: The Spirit to Pursuit Peak Performance on M...

引用

International Symposium on Parallel and Distributed Processing with Applications, ISPA

作者： Yongbin Zhou Junchao Zhang Shuai Zhang Nan Yuan Dongrui Fan Key Laboratory of Computer System and Architecture Institute of Computing Technology Chinese Academy and Sciences Beijing China Chinese Academy of Sciences Beijing Beijing CN

To date, most of many-core prototypes employ tiled topologies connected through on-chip networks. The throughput and latency of the on-chip networks usually become to the bottleneck to achieve peak performance especially for communication intensive applications. Most of studies are focus on on-chip networks only, such as routing algorithms or router micro-architecture, to improve the above metrics. The salient aspect of our approach is that we provide a data management framework to implement high efficient on-chip traffic based on overall many-core system. The major contributions of this paper include that: (1) providing a novel tiled many-core architecture which supports software controlled on-chip data storage and movement management; (2) identifying that the asynchronous bulk data transfer mechanism is an effective method to tolerant the latency of 2-D mesh on-chip networks. At last, we evaluate the 1-D FFT algorithm on the framework and the performance achieves 47.6 Gflops with 24.8% computation efficiency.

关键词： Network-on-a-chip Delay Prototypes Network topology Throughput Routing System-on-a-chip Communication system traffic control computer architecture Memory

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Set of model reduction rules and algorithms for web services composition under orchestration pattern

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Hsi-An Chiao Tung Ta Hsueh/Journal of Xi'an Jiaotong University 2009年第6期43卷 20-23+47页

作者： Yang, Huaizhou Li, Zengzhi Institute of Computer Architecture and Networks Xi'an Jiaotong University Xi'an 710049 China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China

The performance calculation of Web services composition process in large state space is time-consuming, and is difficult to fulfill the real-time performance analysis. Therefore, a process reduction algorithm is presented to accelerate the calculation of system performance. The Web services composition process is modeled using the generalized stochastic Petri net. Through auto-detecting the reductive subnet, some regular structures, such as sequence, choice, concurrent and loop structures, can be eliminated under the precondition of preserving the timing constraints. The sub processes which can be calculated independently are separated. A large scale model can thus be reduced within a certain period. Experimental results with multiform models indicate that the system response time and throughput are obtained rapidly by using the algorithm in the dynamic and adaptive composition process. The algorithm can be applied to online performance analysis of most Web services composition process.

关键词： Stochastic systems

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A stochastic method for controlling the scaling parameters of Cauchy mutation in fast evolutionary programming

A stochastic method for controlling the scaling parameters o...

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Congress on Evolutionary Computation

作者： Yunji Chen Ke Tang Tianshi Chen Key Laboratory of Computer System and Architecture Institute of Computing Technology Chinese Academy of Sciences Beijing China Nature Inspired Computation and Applications Laboratory Department of Computer Science and Technology University of Science and Technology of China Hefei Anhui China

The fast evolutionary programming (FEP) introduced the Cauchy distribution into its mutation operator, thus the performances of EP were promoted significantly on a number of benchmark problems. However, the scaling parameter of the Cauchy mutation is invariable, which has become an obstacle for FEP to reach better performance. This paper proposes and analyzes a new stochastic method for controlling the variable scaling parameters of Cauchy mutation. This stochastic method collects information from a group of individuals randomly selected from the population. Empirical evidence validates our method to be very helpful in promoting the performance of FEP.

关键词： Stochastic processes Genetic mutations Genetic programming Laboratories Random variables Gaussian distribution Control systems Stochastic systems computer architecture computer applications

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