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ICETC 2010 - 2010 2nd International Conference on Education technology and Computer 2010年 4卷 V4311-V4315页

作者： Li, Huiba Peng, Yuxing Lu, Xicheng National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha 410073 China

ISBN: (纸本)9781424463688

Event-driven programming has been a relatively hot topic in distributed systems development. Having worked on these systems for years, we now believe that it is not the best choice. Besides the well-known "stack ripping" problem, we argue that it greatly influences the composability of software modules. Preemptive threads are also short of composability because of data-races and locks. Lacking of composability can result in systems with little vitality. Cooperative threading (or coroutine), on the contrary, is almost free of this problem, so we advocate it as the primary concurrency model for most distributed systems. © 2010 IEEE.

关键词： distributed computer systems

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Using redundant threads for fault tolerance of OpenMP programs

Using redundant threads for fault tolerance of OpenMP progra...

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2010 International Conference in Information science and Applications, ICISA 2010

作者： Fu, Hongyi Ding, Yan Key Laboratory of Science and Technology for National Defence of Parallel and Distributed Processing National University of Defence Tech. Changsha Hunan 410073 China School of Computer National University of Defence Tech. Changsha Hunan 410073 China

ISBN: (纸本)9781424459438

As the wide application of multi-core processor architecture in the domain of high performance computing, fault tolerance for shared memory parallel programs becomes a hot spot of research. For years, checkpointing has been the dominant fault tolerance technology in this field, and recently, many research works have been engaged with it. However, to those programs which deal with large amount of data, checkpointing may induce massive I/O transfer, which will adversely affect scalability. To deal with such a problem, this paper proposes a fault tolerance approach, making use of redundancy, for shared memory parallel programs. Our scheme avoids saving and restoring computational state during the program's execution, hence does not involve I/O operations, so presents explicit advantage over checkpointing in scalability. In this paper, we introduce our approach and the related compiler tool in detail, and give the experimental evaluation result. ©2010 IEEE.

关键词： Fault tolerance

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Two improved GPU acceleration strategies for force-directed graph layout

Two improved GPU acceleration strategies for force-directed ...

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International Conference on Computer Application and System Modeling (ICCASM)

作者： Yong-Xian Wang Zong-Zhe Li Lu Yao Wei Cao Zheng-Hua Wang National Key Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha China National Key Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China

Force directed approach is one of the most widely used methods in graph drawing research. However, the running time is increased intolerablely along with the enlargement of the graph size, which restricts the algorithm's practicability. By the aid of GPU (graphics processing unit) computing platform, we can speed-up the graph layout with low cost, but the existing GPU implementation mainly employees an “one-by-one” style to update the vertex' coordination per iteration, which has a lower convergent rate than the “batch” style which is instead used commonly in traditional CPU implementation. As a result, the aesthetics of graph layout would be decreased if the total running time is restricted. It is hard to achieve both a high speedup factor of GPU over CPU and a high convergent rate in existing GPU computing implementation. In order to solve this problem partially, this paper presents two new strategies to implement the large-scale graph layout on CPU+GPU heteromerous platform to accelerate the force directed layout for graph drawing problem. The numerical computation results show that our GPU implementation can dramatically improve the performance of force-direct layout and is 20 times on a NVIDIA GeForce 9800 GT GPU at 1.44 GHz faster than the one on single-CPU core of Intel Pentium 4 PC at 3.0 GHz for the graph layout with moderate size (typically 1000 vertices).

关键词： Graphics processing unit Gallium nitride Heating

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Towards building efficient content-based publish/subscribe systems over structured P2P overlays

Towards building efficient content-based publish/subscribe s...

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International Conference on parallel processing

作者： Zhang, Shengdong Wang, Ji Shen, Rui Xu, Jie National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha 410073 China School of Computing University of Leeds Leeds LS2 9JT United Kingdom

ISBN: (纸本)9780769541563

In this paper, we introduce a generic model to deal with the event matching problem of content-based publish/ subscribe systems over structured P2P overlays. In this model, we claim that there are three methods (eventoriented, subscription-oriented and hybrid) to make all the matched pairs (event, subscription) meet in a system. By theoretically analyzing the inherent problem of both eventoriented and subscription-oriented methods, we propose PEM (Popularity-based Event Matching), a variant of hybrid method. PEM can achieve better trade-off between event processing load and subscription storage load of a system. PEM has been verified through both mathematical and simulation-based evaluation. © 2010 IEEE.

关键词： Message passing

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Automatic Concurrency Management for distributed applications

Automatic Concurrency Management for distributed application...

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IEEE Symposium on Computers and Communications (ISCC)

作者： Huiba Li Shengyun Liu Yuxing Peng Dongsheng Li National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China

ISBN: (纸本)9781424477548;9781424477555

Building distributed applications is difficult mostly because of concurrency management. Existing approaches primarily include events and threads. Researchers and developers have been debating for decades to prove which is superior. Although the conclusion is far from obvious, this long debate clearly shows that neither of them is perfect. One of the problems is that they are both complex and error-prone. Both events and threads need the programmers to explicitly manage concurrency, and we believe it is just the source of difficulties. In this paper, we propose a novel approach-automatic concurrency management by the runtime system. It dynamically analyzes the programs to discover potential concurrency opportunities; and it dynamically schedules the communication and the computation tasks, resulting in automatic concurrent execution. This approach is inspired by the instruction scheduling technologies used in modern microprocessors, which dynamically exploits instruction-level parallelism. However, hardware scheduling algorithms do not fit software in many aspects, thus we have to design a new scheme completely from scratch. automatic concurrency management is a runtime technique with no modification to the language, compiler or byte code, so it is good at backward compatibility. It is essentially a dynamic optimization for networking programs.

关键词： Concurrent computing Dynamic scheduling Semantics Out of order Runtime Virtual machining

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Nexus: Speculative Execution for Event-Driven Networking Programs

Nexus: Speculative Execution for Event-Driven Networking Pro...

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International Conference on parallel and distributed Systems (ICPADS)

作者： Huiba Li Xicheng Lu Yuxing Peng National Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha China

The efficiency of communication is a key factor to the performance of networking applications, and concurrent communication is an important approach to the efficiency of communication. However, many concurrency opportunities are very difficult to exploit because they depend on some undeterministic conditions. If these conditions are highly predictable, speculative execution can be a very effective approach to cope with the uncertainties. Existing researches on speculation seldom target at networking systems, and none of them can handle the event-driven model that is very popular in such systems. In this paper, we propose Nexus, a novel speculation scheme that supports event-driven networking applications. Nexus analyzes the dependence relationship of events, and performs speculation according to the duality of events and threads. Evaluation on a prototype implementation of nexus shows that this approach can significantly reduces the time needed to complete an event-driven program.

关键词： Containers Internet Prototypes Instruction sets Benchmark testing Protocols Programming

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HiAL-Ckpt: A Hierarchical Application-Level Checkpointing for CPU-GPU Hybrid Systems

HiAL-Ckpt: A Hierarchical Application-Level Checkpointing fo...

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The 5th International Conference on Computer science & Education(第五届国际计算机新技术与教育学术研讨会 ICCSE'10)

作者： Xinhai Xu Yufei Lin Tao Tang Yisong Lin National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China

In light of its powerful computing capacity and high energy efficiency, GPU (graphics processing unit) has become a focus in the research field of HPC (High Performance Computing). CPU-GPU heterogeneous parallel systems have become a new development trend of super-computer. However, the inherent unreliability of the GPU hardware deteriorates the reliability of super-computer. We have researched on the fault-tolerance(FT) technique for CPU-GPU heterogeneous parallel systems, and introduced a new checkpointing mechanism, i.e., the hierarchical application-level checkpointing, for such systems. The basic idea of this new checkpointing mechanism is checkpointing at two independent levels, i.e., CPU level and GPU level, to tolerate CPU and GPU faults respectively. Based on the idea, we have also designed and implemented a hierarchical application-level checkpointing tool ”HiAL-Ckpt”. Using this tool, programmers can insert two kinds of directives, i.e., CPU directives and GPU directives into a program, and the compiler will transform the directives into CPU or GPU checkpointing codes according to their nature. From the case study of SWIM, a test bench from spec2000 benchmark suite, we have demonstrated the validity of the hierarchical application-level checkpointing technique. The experimental results show that the falut-tolerance temporal cost of HiAL-Ckpt for SWIM is only 2.25％, compared with the executing time of SWIM without any FT work.

关键词： GPU:heterogeneous systems:fault-tolerance checkpointing

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Design and Practice on iVCE for Memory System

Design and Practice on iVCE for Memory System

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International Conference on parallel and distributed Systems (ICPADS)

作者： Rui Chu Tian Tian Zhenli Lin National Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha China

As one of the components in iVCE software platform, iVCE/M devotes to the performance improvement of the I/O-intensive and memory-intensive applications with efficient aggregation of distributed memory resources. To facilitate the deployment of iVCE/M, the data locating algorithm with balanced time and space cost, as well as the transparent interface for the legacy applications without code modification, are both significant in the implementation of iVCE/M. We propose the logarithmic search tree based client-side metadata structure to accelerate the data locating using moderate memory consumption, the implicit I/O redirection mechanism, and the implementation of iVCE/M based disk cache system. The experiments with cross domain emulation prove that the scheme is applicable to exploit the distributed memory resources for applications with small granularity I/O accesses.

关键词： Servers Internet Memory management Kernel Driver circuits Prototypes

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Mapping OpenMP Concepts to the Stream Programming Model

Mapping OpenMP Concepts to the Stream Programming Model

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The 5th International Conference on Computer science & Education(第五届国际计算机新技术与教育学术研讨会 ICCSE'10)

作者： Tao Tang Yisong Lin Xiaoguang Ren National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China

OpenMP is a widely used parallel programming model on traditional multi-core processors. Generally, OpenMP is used to develop fine-grained parallelism through a multithread model. Stream programming model is a new kind of parallel programming model for stream architectures. OpenMP bears a resemblance to the stream programming model at some level. The transformation between the two models has attracted much attention from the research community, since it is the foundation of porting programs between the two architectures. Most related researches focus on the efficiency of porting existing parallel programs to the new architectures such as GPUs. Very few of these studies, however, focus on the portative problem systematically, namely, what kind of parallel programs can be or should be transplanted into stream programs and mapped to run on the stream processors. In this paper, we study the mapping relationship of parallel mechanism in OpenMP to the stream programming model, and point out those parallel mechanisms in OpenMP that are infeasible or undesirable for stream programs. By analyzing two typical benchmarks, we draw the conclusion that a majority of scientific applications are suitable to be mapped to the stream programming model. Our conclusion effectively validates the idea of accelerating scientific applications with the stream processors.

关键词： OpenMP:stream programming model:parallel mechanism:mapping

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A Data Communication Scheduler for Stream Programs on CPU-GPU Platform

A Data Communication Scheduler for Stream Programs on CPU-GP...

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International Conference on Computer and Information technology (CIT)

作者： Tao Tang Xinhai Xu Yisong Lin National Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha China

In recent years, heterogeneous parallel system have become a focus research area in high performance computing field. Generally, in a heterogeneous parallel system, CPU provides the basic computing environment and special purpose accelerator (GPU in this paper) provides high computing performance. However, the overall performance of the system is prone to be limited by the data communication between the CPU and the GPU. Data communication is typically used to synchronize the array on the CPU and the stream (in AMD's terminology) on the GPU. In many cases, programmers just add data synchronization for each GPU invoking independently. It is easy to program in this manner but much redundant communication may be introduced, which will dramatically degrade the overall performance. To alleviate this problem, based on the stream programming model, we propose a heuristic data communication schedule approach in this paper. By analyzing the state transition of stream/array data pair, relaxing the synchronization strategy conditionally and considering optimization for branch and loop control structure, our approach can significantly reduce the redundant data communication in most cases.

关键词： Graphics processing unit Data communication Arrays Kernel Streaming media Schedules

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