Recovering from node failures is a critical issue in distributed database systems. In conventional log-based recovery protocols, the nodes providing recovery service may be overburdened, especially when the recovery i...
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ISBN:
(纸本)0769520693
Recovering from node failures is a critical issue in distributed database systems. In conventional log-based recovery protocols, the nodes providing recovery service may be overburdened, especially when the recovery is resource consuming. In this paper, an agent-based dynamic recovery protocol is presented. It divides the whole recovery process into three major steps: log-recovery, agent-recovery, and synchronization. The key idea of this protocol is to cache new database operations initiated during recovery into agents. All these cached operations are then replayed independently for further recovery. The analysis indicates that the new protocol can minimize internode's dependency and improve recovery speed. As a result, system failure rate is cut down and the overall performance gets improved.
Random walks constitute an attractive technique in distributed computing. In this paper, we present an original method using relationship between electrical resistance and random walks, to automatically compute quanti...
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ISBN:
(纸本)0769520693
Random walks constitute an attractive technique in distributed computing. In this paper, we present an original method using relationship between electrical resistance and random walks, to automatically compute quantities such as cover time, and more generally any processing time measure defined through hitting times. This method comes from electrical theory by using Millman's theorem.
In this paper, a parallel dynamic load balancing algorithm;which offers a good trade-off between the balancing degree and communication costs;is proposed. The proposed algorithm is analyzed, investigated, and implemen...
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ISBN:
(纸本)0769520693
In this paper, a parallel dynamic load balancing algorithm;which offers a good trade-off between the balancing degree and communication costs;is proposed. The proposed algorithm is analyzed, investigated, and implemented. Also, a new mathematical solution for that algorithm is presented. The analytical solution is tested on standard task graphs (STG) as common test-bed benchmarks. All the different parameters concerned with processors, memory, interconnection networks, and task programs are also presented. The new proposed algorithm is compared and evaluated with a traditional dynamic load balancing one. Experimental results are presented by considering a set of criteria for evaluating the overall performance. Simulation and analytical results proved that the proposed algorithm outperforms the chosen one.
In this paper, we study a high-performance Heterogeneous distributed System (HDS) that is employed as a computing platform or grid. Precisely, we study the problem of scheduling a large number of CPU-intensive tasks o...
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ISBN:
(纸本)0769520693
In this paper, we study a high-performance Heterogeneous distributed System (HDS) that is employed as a computing platform or grid. Precisely, we study the problem of scheduling a large number of CPU-intensive tasks on such systems. In this study, the time spent by a task in the system is considered as the main issue that needs to be minimized. The proposed techniques of scheduling dynamic tasks consist of two heuristic algorithms;Recursive Neighbor Search (RNS) and Augmented Tabu-Search (ATS) algorithm. Our technique does not address directly the load-balancing problem since it is completely unrealistic in such large environments, but we will show that even a non-perfectly load-balanced system can behave reasonably well by taking into account the tasks' time demands. These algorithms are compared to a well known scheduling algorithm, in order to compare, evaluate, and clarify their performance.
As software distributed Shared Memory(DSM) systems become attractive on larger clusters, the focus of attention moves toward improving the reliability of systems. In this paper, we propose a lightweight logging scheme...
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ISBN:
(纸本)0769520693
As software distributed Shared Memory(DSM) systems become attractive on larger clusters, the focus of attention moves toward improving the reliability of systems. In this paper, we propose a lightweight logging scheme, called remote logging, and a recovery protocol for home-based DSM. Remote logging stores coherence-related data to the volatile memory of a remote node. The logging overhead can be moderated with high-speed system area network and user-level DMA operations supported by modern communication protocols. Remote logging tolerates multiple failures if the backup nodes of failed nodes are alive. It makes the reliability of DSM grow much higher. Experimental results show that our fault-tolerant DSM has low overhead compared to conventional stable logging and it can be effectively recovered from some concurrent failures.
This paper describes an on-chip bus architecture targeted for the globally asynchronous locally synchronous system-on-chip design strategy. The proposed pipelined bus structure is composed of asynchronously interactin...
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ISBN:
(纸本)0780379799
This paper describes an on-chip bus architecture targeted for the globally asynchronous locally synchronous system-on-chip design strategy. The proposed pipelined bus structure is composed of asynchronously interacting segments which can operate in parallel. The bus is segmented using transfer stages which partition bus into a set of point-to-point interconnects. Self-timed arbitration and control is distributed among the pipelined stages to enable parallel operation of distinct segments, to prevent problems present in a globally clocked system, and to increase design modularity. In a 0.18 mum technology, each bus segment is capable of transferring data at a maximum throughput of 1.2 giga data items per second concurrently in both directions.
distributed Database Management systems offer advantages and new possibilities to centralized database systems. However, some aspects and issues need to receive further consideration. Concurrency control is one of the...
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ISBN:
(纸本)0769520693
distributed Database Management systems offer advantages and new possibilities to centralized database systems. However, some aspects and issues need to receive further consideration. Concurrency control is one of these aspects that has to be improved in order to increase system performance. Strict Two Phase locking s2pl is the con-currency control mechanism that is used in most commercial database systems. The performance of s2pl can be greatly improved using speculative techniques with speculative Two Phase Locking algorithms sp2pl. In this paper we present extensions of the sp2pl algorithm based on Wait Depth Limited techniques wdl-sp2pl. A comprehensive simulation model is developed from which the performance of sp2pl and the wdl-sp2pl's are evaluated. Our analysis also shows that the new algorithms give a better performance than sp2pl, maintaining the robustness of sp2pl.
Computational Grids are emerging as a new infrastructure for Internet-based parallel and distributed computing. They enable the sharing, exchange, discovery, and aggregation of resources distributed across multiple ad...
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We present a numerical study of several parallel algebraic preconditioners, which speed up the convergence of Krylov iterative methods when solving large-scale linear systems. The studied algebraic preconditioners are...
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In this work we describe two sequential algorithms and their parallel counterparts for solving nonlinear systems, when the Jacobian matrix is symmetric and positive definite. This case appears frequently in unconstrai...
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