software transactional memory systems enable a programmer to easily write concurrent data structures such as lists, trees, hashtables, and graphs, where non-conflicting operations proceed in parallel. Many of these st...
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software transactional memory systems enable a programmer to easily write concurrent data structures such as lists, trees, hashtables, and graphs, where non-conflicting operations proceed in parallel. Many of these structures take the abstract form of a dictionary, in which each transaction is associated with a search key. By regrouping transactions based on their keys, one may improve locality and reduce conflicts among parallel transactions. In this paper, we present an executor that partitions transactions among available processors. Our key-based adaptive partitioning monitors incoming transactions, estimates the probability distribution of their keys, and adaptively determines the (usually nonuniform) partitions. By comparing the adaptive partitioning with uniform partitioning and round-robin keyless partitioning on a 16-processor SunFire 6800 machine, we demonstrate that key-based adaptive partitioning significantly improves the throughput of finegrained parallel operations on concurrent data structures.
Focused around the field of the exploitation and the administration of high performance large-scale parallelsystems, this article describes the work carried out on the deployment of environment on high computing clus...
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ISBN:
(纸本)9781424400546
Focused around the field of the exploitation and the administration of high performance large-scale parallelsystems, this article describes the work carried out on the deployment of environment on high computing clusters and grids. We initially present the problems involved in the installation of an environment (OS, middleware, libraries, applications...) on a cluster or grid and how an effective deployment tool, Kadeploy2, can become a new form of exploitation of this type of infrastructures. We present the tool's design choices, its architecture and we describe the various stages of the deployment method, introduced by Kadeploy2. Moreover, we propose methods on the one hand, for the improvement of the deployment time of a new environment; and in addition, for the support of various operating systems. Finally, to validate our approach we present tests and evaluations realized on various clusters of the experimental grid Grid5000
This paper deals with scheduling in software development organizations. A new version of the software project scheduling problem (SPSP) is considered that takes into account the phenomenon of learning and forgetting. ...
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Masonry arch bridges comprise a significant proportion of the bridge stock in many countries. Due to increased traffic loads and possible deterioration of the bridge structure, it is essential that the load carrying c...
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ISBN:
(纸本)9780415621267
Masonry arch bridges comprise a significant proportion of the bridge stock in many countries. Due to increased traffic loads and possible deterioration of the bridge structure, it is essential that the load carrying capacity of such bridges be regularly assessed. Environmental benefits can be gained if the assessment provides an accurate evaluation of the capacity of the bridge, thereby avoiding unnecessary remedial work or bridge replacement. Several methods are currently used to assess masonry arch bridges including the popular modified MEXE method and mechanism analysis. An issue of particular interest is how the loads are distributed transversely in the arch. The current load model for masonry arch bridges calls for the utilisation of an effective strip when dealing with the transverse distribution of an applied load. In this paper LUSAS finite element analysis (FEA) software is used to assess transverse load patterns on masonry arch bridges. An arch is modelled using thick shell elements to represent voussoirs and a reduced stiffness is assigned to the mortar joints between each voussoir. The overall aim is to develop a load distribution model that improves upon current mechanism methods for the design and assessment of masonry arch bridges.
High-end machines at modern HPC centers are constantly undergoing hardware and system software upgrades - necessitating frequent rebuilds of application codes. The number of possible combinations of compilers, librari...
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High-end machines at modern HPC centers are constantly undergoing hardware and system software upgrades - necessitating frequent rebuilds of application codes. The number of possible combinations of compilers, libraries, application build configurations, differing hardware architectures, etc, makes the process of building applications very onerous, requiring expert build knowledge from different domains. Our ongoing Harness Workbench Toolkit (HWT) project aims to foster and streamline the entire build process on heterogeneous computational platforms. This paper focuses on a key research issue of the HWT that regards facilitating and enhancement portability of build systems across multifarious machines, with particular respect to scientific software commonly used in the HPC community. The article presents a novel HWT approach based on the concept of generic build systems and profiles which encapsulate build knowledge provided independently by relevant experts. The paper describes profiles, the logistics of storing and retrieving build information, and interfacing to user-guided builds. We also report on experiences with applying the HWT approach to two scientific production codes (CPMD, GAMESS) on Cray XT4.
This paper has provided a first step towards solid theoretical foundations of large scale distributedsystems. It has focused on applying complex systems theories SOC and HOT to data management solutions in P2P grids....
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This paper has provided a first step towards solid theoretical foundations of large scale distributedsystems. It has focused on applying complex systems theories SOC and HOT to data management solutions in P2P grids. It argues that replica management solution over OpenDHT, the state of the art DHT deployment, is based on SOC and consequently achieves robustness even in the presence of churn but not optimal performance.
Binary function embedding models are applicable to various downstream tasks within IoT device softwaresystems and have demonstrated advantages in numerous binary analysis tasks, such as vulnerability (homologous) fun...
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distributed real-time systems play an increasingly vital role in our daily life. The most important aspect of such systems is the scheduling algorithm, which must guarantee that every job in the system will meet its d...
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ISBN:
(纸本)9781424434497
distributed real-time systems play an increasingly vital role in our daily life. The most important aspect of such systems is the scheduling algorithm, which must guarantee that every job in the system will meet its deadline. In this paper we evaluate by simulation the performance of strategies for the scheduling of parallel jobs (gangs) in a homogeneous distributed real-time system with possible software faults. We provide an alternative version for each scheduling policy, which allows imprecise computations, and we propose a performance metric applicable to our problem. Our simulation results show that the alternative versions of the algorithms exhibit promising performance.
This extended abstract describes the keynote presentation "stochastically robust resource management in heterogeneous parallel computing systems," to be given by H. J. Siegel. What does it mean for a compute...
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This extended abstract describes the keynote presentation "stochastically robust resource management in heterogeneous parallel computing systems," to be given by H. J. Siegel. What does it mean for a computer system to be "robust"? How can robustness be described? How does one determine if a claim of robustness is true? How can one decide which of two systems is more robust? Often people state that their system software component, piece of hardware, application code, or technique is "robust," but never define what they mean by "robust." How does one determine if a claim of robustness is true when it is not defined? Furthermore, without a definition, robustness cannot be quantified, so if two people claim to have robust computing systems, for example, how can one decide which is the more robust? These are the types of issues we address in this keynote presentation. We study robustness in the context of resource allocation in heterogeneous parallel and distributed computing systems, but the robustness concepts presented have broad applicability. In heterogeneous parallel and distributed computing environments, a collection of different machines is interconnected and provides a variety of computational capabilities. These capabilities can be used to execute a workload composed of different types of applications, each of which may consist of multiple tasks, where the tasks have diverse computational requirements. The execution times of a task may vary from one machine to the next, and just because some machine A is faster than some machine B for task 1 does not mean it will be faster for task 2. Furthermore, there can be inter-task data dependencies. Tasks must share the computing and communication resources of the system. A critical research problem is how to allocate resources to tasks to optimize some performance objective. However, systems frequently have degraded performance due to uncertainties, such as unexpected machine failures, changes in system workload, or i
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