In this paper, a new event scheduling mechanism XEQ and a new rollback procedure rb-messages are proposed for use in optimistic logic simulation. We incorporate both of these techniques in a simulator XTW. XTW groups ...
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ISBN:
(纸本)0769523838
In this paper, a new event scheduling mechanism XEQ and a new rollback procedure rb-messages are proposed for use in optimistic logic simulation. We incorporate both of these techniques in a simulator XTW. XTW groups LPs into clusters, and makes use of a multi-level queue,XEQ, to schedule events in the cluster. XEQ has an O(1) event scheduling time complexity. Our new rollback mechanism replaces the use of anti-messages by an rb-message, and eliminates the need for an output queue at each LP. Experimental comparisons to Time Warp reveal a superior performance on the part of XTW, while experimental results over large circuits (5-million-gate to 25-million-gate) shows XTW scales well with boththe size of circuits and the number of processors.
In this work, we propose a heuristic algorithm based on Genetic Algorithm for the task-to-processor mapping problem in the context of local-memory multiprocessors with a hypercube interconnection topology. Hypercube m...
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ISBN:
(纸本)0769500595
In this work, we propose a heuristic algorithm based on Genetic Algorithm for the task-to-processor mapping problem in the context of local-memory multiprocessors with a hypercube interconnection topology. Hypercube multiprocessors have offered a cost effective and feasible approach to supercomputing through parallelism at the processor level by directly connecting a large number of low-cost processors with local memory which communicate by message passing instead of shared variables. We use concepts of the graph theory (task graph precedence to represent par allel programs, graph partitioning to solve the program decomposition problem, etc.) to model the problem. this problem is NP-complete which means heuristic approaches must be adopted. We develop a heuristic algorithm based on Genetic Algorithms to solve it.
this paper introduces Simultaneous Speculation Scheduling, a new compiler technique that enables speculative execution of alternative program paths. In our approach concurrently executed threads are generated that rep...
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ISBN:
(纸本)0769500595
this paper introduces Simultaneous Speculation Scheduling, a new compiler technique that enables speculative execution of alternative program paths. In our approach concurrently executed threads are generated that represent alternative program paths. Each thread is the result of a speculation on the outcome of one or more branches. All threads are simultaneously executed although only one of them follows the eventually correct program path. Our technique goes beyond the capabilities of usual global instruction scheduling algorithms, because we overcome most of the restrictions to speculative code motion. the architectural requirements are the ability to run two or more threads in pal allel, and an enhanced instruction set to control threads. Our technique aims at multithreaded architectures, in particular simultaneous multithreaded, nanothreaded, and microthreaded processors, but can be modified for multiscalar, datascalar, and trace processors. We evaluate our approach using program kernels from the SPECint benchmark suite.
the proceedings contain 8 papers. the topics discussed include: enabling python to execute efficiently in heterogeneous distributed infrastructures with PyCOMPSs;efficient pattern matching in python;real-time financia...
ISBN:
(纸本)9781450354806
the proceedings contain 8 papers. the topics discussed include: enabling python to execute efficiently in heterogeneous distributed infrastructures with PyCOMPSs;efficient pattern matching in python;real-time financial risk measurement of dynamic complex portfolios with Python and PyOpenCL;Python in the NERSC exascale science applications program for data;real-time thermal medium-based breathing analysis with Python;GPUMap: a transparently GPU-accelerated Python map function;nbodykit: a Python toolkit for cosmology simulations and data analysis on parallel HPC systems;and Python and HPC for high energy physics data analyses.
distributedsimulation enables participants situated in different geographical locations to share a common virtual world, which is called a distributed Virtual Environment (DVE). Among the different research topics co...
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ISBN:
(纸本)0769520367
distributedsimulation enables participants situated in different geographical locations to share a common virtual world, which is called a distributed Virtual Environment (DVE). Among the different research topics concerned with DVEs, there is a current trend of linking Multi-Agent systems and DVEs together. Withthe properties of autonomy, social ability, reactivity and proactiveness, agents can be used to represent entities in DVEs, where fast and accurate decision making is a determining factor of the whole environment. this paper provides a description of integrating agents into an HLA-based distributedsimulation. It focuses on how to construct the sensor of an agent with different interest management schemes. Using the JADE (Java Agent DEvelopment Framework) agent toolkit and the High Level Architecture (HLA) in our prototype, a minesweeping game, we outline two different implementations of this game. Due to the dynamic characteristics of agents, a problem of overdue information from the environment is discussed, and we propose an enlarged subscription region method to solve this problem. Moreover, advisories provided by the HLA are adopted to reduce the overheads. Conclusions are drawn based on the experimental results of these implementations.
Server replication is an approach often used to improve service access efficiency and availability for a large number of clients. this paper adopts a simple service model and investigates a set of efficient algorithms...
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ISBN:
(纸本)0769521355
Server replication is an approach often used to improve service access efficiency and availability for a large number of clients. this paper adopts a simple service model and investigates a set of efficient algorithms for server selection in an anycast group under the condition of imprecise network delay. the algorithms use ticket-based probing approach to search the path with short delay and probe the server load at the same time and try to optimize the server and path delay at the same time. the simulation results demonstrate that our algorithms are efficient in terms of server response time for sever selection compared with several other server selection algorithms.
Cluster analysis is a valuable tool for exploratory pattern analysis, especially when very little a priory knowledge about the data is available. distributed systems, based on high speed intra-net connections, provide...
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ISBN:
(纸本)0769522556
Cluster analysis is a valuable tool for exploratory pattern analysis, especially when very little a priory knowledge about the data is available. distributed systems, based on high speed intra-net connections, provide new tools in order to design new and faster clustering algorithms. Here, a parallel genetic algorithm for clustering called PGAC is described. the used strategy of parallelization is the island model paradigm where different populations of chromosomes (called demes) evolve locally to each processor and from time to time some individuals are moved from one deme to another. Experiments have been performed for testing the benefits of the parallelisation paradigm in terms of computation time and correctness of the solution.
Debuggers are critical tools for software development. the design and implementation of a source-level debugging system that enables the HPF programmer to observe the behavior of the program? at the level at which the...
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ISBN:
(纸本)0769500595
Debuggers are critical tools for software development. the design and implementation of a source-level debugging system that enables the HPF programmer to observe the behavior of the program? at the level at which the program has been developed present unique challenges. the main requirement put on an HPF debugger is to observe and control the state of many processors, to summarize and present distributed information in a concise and clear way, in terms of the source program. To be practical, the debugger has to support interactive source-level debugging of large-scale applications on large machines. In this paper Me define design goals for HPF debuggers and present an architecture of an advanced HPF debugging sq,stem DeHiFo, which addresses several challenges involved and provides significant contributions to existing debugging technology! An HPF debugger is a rather complex system. Its development requires a systematic cooperation between several partners. DeHiFo is an excellent example of cooperation and technology transfer among research teams working at different universities.
DASUD (Diffusion Algorithm Searching Unbalanced Domains) is a totally distributed load-balancing algorithm which belongs to the nearest-neighbors class. DASUD detects unbalanced domains (a processor and its immediate ...
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ISBN:
(纸本)0769500595
DASUD (Diffusion Algorithm Searching Unbalanced Domains) is a totally distributed load-balancing algorithm which belongs to the nearest-neighbors class. DASUD detects unbalanced domains (a processor and its immediate neighbors) and corrects this situation by allowing load movements between non-connected processors. DASUD has been evaluated by comparison with two well-known nearest-neighbors load balancing strategies, namely, the CDE (Generalized Dimension Exchange) and the SID (Sender Initiated Diffusion) by considering a large set of initial load distributions. these distributions were applied to ring, torus and hypercube topologies, and the number of processors ranged from 8 to 128. FI-om these experiments we have observed that DASUD outperforms the other strategies used in the comparison as it provides the best trade-off between the balance degree obtained at the final state and the number of iterations required to reach this stare.
In this paper we propose a systematic approach to performance analysis of workflow applications on the Grid. We introduce an ideal model for the workflow execution time and explain the difference to the real measured ...
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ISBN:
(纸本)9781424403431
In this paper we propose a systematic approach to performance analysis of workflow applications on the Grid. We introduce an ideal model for the workflow execution time and explain the difference to the real measured times based on a hierarchy of performance overheads for Grid computing. We describe how to systematically measure and compute the overheads from individual activities to entire workflow applications. We adjusted well-known parallel processing metrics to the scope of Grid computing, comprising speedup and efficiency. We have implemented and largely automatised our analysis approach in the context of the ASKALON Grid application development and computing environment. We present experimental results that show detailed overhead analysis of two real-world workflow applications executed in a national Grid environment.
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