Advances in high performance computing, communications, and user interfaces enable developers to construct increasingly interactive high performance applications. The Falcon system presented in this paper supports such interactivity by providing runtime libraries, tools, and user interfaces that permit the on-line monitoring and steering of large-scale parallel codes. The principal aspects of Falcon described in this paper are its abstractions and tools for capture and analysis of application-specific program information, performed on-line, with controlled latencies and scalable to parallel machines of substantial size. In addition, Falcon provides support for the on-line graphical display of monitoring information, and it allows programs to be steered during their execution, by human users or algorithmically. This paper presents our basic research motivation, outlines the Falcon system's functionality, and includes a detailed evaluation of its performance characteristics in light of i...

Program monitoring and steering systems can provide invaluable insight into the behavior of complex parallel and distributed applications. But the traditional event-streambased approach to program monitoring does not scale well with increasing complexity. This paper introduces the Mirror Object Model, a new approach for program monitoring and steering systems. This approach provides a higher-level object-based abstraction that links the producer and the consumer of data and provides a seamless model which integrates monitoring and steering computation. We also introduce the Mirror Object Steering System (MOSS), an implementation of the Mirror Object Model based on CORBAstyle objects. This paper demonstrates the advantages of MOSS over traditional event-stream-based monitoring systems in handling complex situations. Additionally, we show that the additional functionality of MOSS can be achieved without significant performance penalty. 1 Introduction As applications have grown more com...

Current communications tools and libraries for high performance computing are designed for platforms and applications that exhibit relatively stable computational and communication characteristics. In contrast, the demands of (1) mixed environments in which high performance applications interact with multiple end users, visualizations, storage engines, and I/O engines -- termed `distributed laboratories' in our research -- and (2) high performance collaborative computing applications in general, exhibit additional complexities in terms of dynamic behaviors. This paper explores the communication requirements of distributed laboratories, and it describes the DataExchange communication infrastructure supporting high performance interactive and collaborative applications. Keywords: parallel, distributed, communication, dynamic, interactive 1 COMMUNICATION SUBSTRATES Communication tools and libraries for high performance distributed computing have evolved substantially during the last fe...

We explore the use of compression methods to improve the middleware-based exchange of information in interactive or collaborative distributed applications. In such applications, good compression factors must be accompanied by compression speeds suitable for the data transfer rates sustainable across network links. Our approach combines methods that continuously monitor current network and processor resources and assess compression effectiveness, with techniques that automatically choose suitable compression techniques. By integrating these techniques into middleware, there is little need for end user involvement, other than expressing the target rates of data transmission. The resulting network- and user-aware compression methods are evaluated experimentally across a range of network links and application data, the former ranging from low end links to homes, to wide-area Internet links, to high end links in intranets, the latter including both scientific (binary molecular dynamics data) and commercial (XML) data sets. Results attained demonstrate substantial improvements of this adaptive technique for data compression over non-adaptive approaches, where better compression methods are used when CPU loads are low and/or network links are slow, and where less effective and typically, faster compression techniques are used in high end network infrastructures. Index terms-- communication lines, compression I.

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. Research areas that require interactive visualization of simulation data

This paper presents JECho, a Java-based communication infrastructure for collaborative high performance applications. JECho implements a publish/subscribe communication paradigm, permitting distributed, concurrently executing sets of components to provide interactive service to collaborating end users via event channels. JECho’s efficient implementation enables it to move events at rates higher than other Java-based event system implementations. In addition, using JECho’s eager handler concept, individual event subscribers can dynamically tailor event flows to adapt to runtime changes in component behaviors and needs, and to changes in platform resources. JECho has been used to build distributed collaborative scientific codes as well as ubiquitous applications. Its event interface and eager handler mechanism have been shown flexible and in some scenarios, critical to the successful implementations of such applications. This paper’s microbenchmarks demonstrate that, with optimizations and customizations of the runtime system and the object transport layer, TCP-based reliable group communication in Java can reach good performance levels. These benchmark results also suggest that it is viable to use JECho to build large-scale, high-performance event delivery systems. JECho’s implementation is in pure Java. Its group-cast communication layer is based on Java Sockets, and it also runs in some embedded environments that currently lack standard object serialization support. 1.

There is growing interest in run-time detection as parallel and distributed systems grow larger and more complex. This work targets run-time analysis of complex, interactive scientific applications for purposes of attaining scalability improvements with respect to the amount and complexity of the data transmitted, transformed, and shared among different application components. Such improvements are derived from using database techniques to manipulate data streams. Namely, by imposing a relational model on the data streams, constraints on the stream may be expressed as database queries evaluated against the data events comprising the stream. The application in this paper is to a safety-critical system. This paper also presents a tool, dQUOB, Dynamic QUery OBjects, which (1) offers the means for dynamic creation of queries and for their application to large data streams, (2) permits implementation and runtime use of multiple ‘query optimization ’ techniques, and (3) supports dynamic reoptimization of queries based on streams ’ dynamic behavior. 1.

This paper presents JECho, a Java-based communication infrastructure for collaborative high performance applications. JECho implements a publish/subscribe communication paradigm, permitting distributed concurrent sets of components to provide interactive service to collaborating end users via event channels. JECho's eager handler concept allows individual event subscribers to dynamically tailor event flows to adapt to runtime changes in component behaviors and needs, and to changes in platform resources. Benchmark results suggest that JECho may be used for building large-scale, high-performance event delivery systems, which can efficiently adapt to changes in user needs or the environment using eager handlers.

This paper presents the design, implementation and experimental eval- uation of DIOS (Distributed Interactive Object Substrate), an interactive object infrastructure to enable the runtime monitoring, interaction and computational steering of parallel and distributed applications. DIOS en- ables application objects (data structures, algorithm) to be enhanced with sensors and actuators so that they can be interrogated and controlled