RMOST: A Shared Memory Model for Online Steering.
ABSTRACT Online steering means to visualize the current state of an application which includes application data and/or performance
data, and to modify data in the application. Thus, in online steering the application as well as the steering tool must concurrently
access and modify the same data at run time. In this paper a new model for online steering is presented which models the mechanism
of online steering as access to a distributed shared memory. The integrity requirements of the steered application are analyzed.
The integrity can be ensured through an appropriate consistency model. Finally, the online steering system RMOST is presented
which is based on the distributed shared memory model and can be used to steer Grid jobs from the High Energy Physics experiment
- SourceAvailable from: O. Coulaud[show abstract] [hide abstract]
ABSTRACT: The on-line visualization and the computational steering of parallel simulations come up against a serious coherence problem. Indeed, data distributed over parallel processes must be accessed carefully to ensure they are presented to the visualization system in a meaningful way. In this paper, we present a solution to the coherence problem for structured parallel simulations. We introduce a hierarchical task model that allows to better grasp the complexity of simulations, too often considered as “single-loop” applications. Thanks to this representation, we can schedule in parallel the request treatments on the simulation processes and satisfy the temporal coherence.01/2004;
Conference Proceeding: Visualization in grid computing environments[show abstract] [hide abstract]
ABSTRACT: Grid computing provides a challenge for visualization system designers. In this research, we evolve the dataflow concept to allow parts of the visualization process to be executed remotely in a secure and seamless manner. We see dataflow at three levels: an abstract specification of the intent of the visualization; a binding of these abstract modules to a specific software system; and then a binding of software to processing and other resources. We develop an XML application capable of describing visualization at the three levels. To complement this, we have implemented an extension to a popular visualization system, IRIS Explorer, which allows modules in a dataflow pipeline to run on a set of grid resources. For computational steering applications, we have developed a library that allows a visualization system front-end to connect to a simulation running remotely on a grid resource. We demonstrate the work in two applications: the dispersion of a pollutant under different wind conditions; and the solution of a challenging numerical problem in elastohydrodynamic lubrication.Visualization, 2004. IEEE; 11/2004
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ABSTRACT: Memory consistency models have been developed to specify what values may be returned by a read given that, in a distributed system, memory operations may only be partially ordered. Before this work, consistency models were defined independently. Each model followed a set of rules which was separate from the rules of every other model. In our work we have defined a set of four consistency properties. Any subset of the four properties yields a set of rules which constitute a consistency model. Every consistency model previously described in the literature can be defined based on our four properties. Therefore, we present these properties as a unfied theory of shared memory consistency.09/2002;