Browsing by Author "England, Darin"
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Item A Stochastic Control Model for Leasing Computational Resources(2004-02-20) England, Darin; Weissman, JonWe present a model for determining the optimal resource leasing policy for a dynamic grid service. The model assumes that the demand for the service as well as the actual execution times are unknown, but can be estimated. We cast the problem in a Dynamic Programming framework and we are able to show that the model can make good resource leasing decisions in the face of such uncertainties. In particular, we use the model to decide how many resources should be leased for the service and for how long. The results show that use of the model reduces the cost of leasing computational resources and significantly reduces the variance of the cost.Item Costs and Benefits of Load Sharing in the Computational Grid(2003-08-26) England, Darin; Weissman, JonWe present an analysis of the costs and benefits of load sharing of parallel jobs in the computational grid. We begin with a workload generation model that captures the essential properties of parallel jobs and use it as input to a grid simulation model. Our experiments are performed for both homogeneous and heterogeneous grids. We measured average job slowdown with respect to both local and remote jobs and we show that, with some reasonable assumptions concerning the migration policy, load sharing proves to be beneficial when the grid is homogeneous, and that load sharing can adversely affect job slowdown for lightly-loaded machines in a heterogeneous grid. With respect to the number of sites in a grid, we find that the benefits obtained by load sharing do not scale well. Small to modest-size grids can employ load sharing as effectively as large-scale grids. We also present and evaluate an effectivescheduling heuristic for migrating a job within the grid.Item Supporting the Dynamic Grid Service Lifecycle(2004-11-17) Weissman, Jon; Kim, Seonho; England, DarinThis paper presents an architecture and implementation for a dynamic OGSA-based Grid service architecture that extends GT3 to support dynamic service hosting - where to host and re-host a service within the Grid in response to service demand and resource fluctuation. Our model goes beyond current OGSI implementations in which the service is presumed to be