Proceedings 11th IEEE International Symposium on High Performance Distributed Computing

In this paper we present a novel methodology for improving the performance and dependability of application-level messaging in Grid systems. Based on the Network Weather Service, our system uses nonparametric statistical forecasts of request-response times to automatically determine message timeouts. By choosing a timeout based on predicted network performance, the methodology improves application and Grid service performance as extraneous and overly-long timeouts are avoided. We describe the technique, the additional execution and programming overhead it introduces, and demonstrate the effectiveness using a wide-area test application.

In this paper, we argue that an exclusively inactive interface to directory services can hinder server scalability and indirectly restrict the behavior of potential applications. We propose to extend directory services' interfaces with a proactive mode by which clients can express their interest in (and be notified of) changes in the environment. These notification channels can be subsequently customized on a per-client basis through client-specified filters. Finally, in order to simplify the handling of client/server failures we adopt a leasing model for client registration to (and customization of) a notification channel. To validate our approach, we have designed and implemented the Proactive Directory Service (PDS).

Increasing complexity of distributed applications and commodity of resources through grids are making the tasks of deploying those applications harder. There is a clear need for standard tools allowing versatile deployment and analysis of distributed applications. We present here a solution for the deployment and monitoring of applications written using ProActive, an experimental Java-based library for concurrent, distributed and mobile computing. We describe the use of XML-based descriptor for the deployment part of a distributed application and the use of IC2D (Interactive Control and Debugging of Distribution), for the monitoring and steering of the running application. Those ideas, concepts, and experiments are a contribution towards the construction of integrated environments for component-based grid programming.

Quickly transmitting large datasets in the context of distributed computing on wide area networks can be achieved by compressing data before transmission, However such an approach is not efficient when dealing with higher speed networks. Indeed, the time to compress a large file and to send it is greater than the time to send the uncompressed file. In this paper we explore and enhance an algorithm that allows us to overlap communications with compression and to automatically adapt the compression effort to currently available network and processor resources.

Several recently proposed infrastructures permit client applications to interact with distributed network-accessible services by simply "plugging in" into a substrate that provides essential functionality, such as naming, discovery, and multi-protocol binding. However much work remains before the interaction can be considered truly seamless in the sense of adapting to the characteristics of the heterogeneous environments in which clients and services operate. This paper describes a novel approach for addressing this shortcoming: the partitionable services framework, which enables services to be flexibly assembled from multiple components, and facilitates transparent migration and replication of these components at locations closer to the client while still appearing as a single monolithic service. The framework consists of three pieces: (1) declarative specification of services in terms of constituent components; (2) run-time support for dynamic component deployment; and (3) planning policies, which steer the deployment to accomodate underlying environment characteristics. We demonstrate the salient features of the framework and highlight its usability and performance benefits with a case study involving a security-sensitive mail service.

With the advent of Grid computing, scheduling strategies for distributed heterogeneous systems have either become irrelevant or have to be extended significantly to support Grid dynamics. In this paper, we describe a metascheduling architecture for a Grid system that takes into account both the application and system level considerations. Results are presented to demonstrate the usefulness of the metascheduler.

Discovery Net is an application layer for providing grid-based knowledge discovery services. These services allow scientists to create and manage complex knowledge discovery workflows that integrate data and analysis routines provided as remote services. They also allow scientists to store, share and execute these workflows as well as publish them as new services. Discovery Net provides a higher level of abstraction of the Grid for knowledge discovery activities, thus separating the end-users from resource management issues already handled by existing and emerging standards.

Computational grids provide mechanisms for sharing and accessing large and heterogeneous collections of remote resources such as computers, online instruments, storage space, data, and applications. Resources are requested by specifying a set of desired attributes. Resource attributes have various degrees of dynamism, from mostly static attributes, such as operating system version, to highly dynamic ones, such as available network bandwidth or CPU load. Another dimension of dynamism is introduced by variable and highly diverse sharing policies: resources are made available to the grid community based on locally defined and potentially changing policies.

Computational portal developers often reimplement functionality found in existing portals because there are no common discovery and access mechanisms in place to enable sharing of portal functions. The Web services architecture provides an implementation independent, protocol based mechanism for entities to find, share, and invoke remote services. We developed complementary web services at SDSC and IU that generate batch scripts for different batch queuing schedulers.

Rather than painful, manual, static, per-connection optimization of TCP buffer sizes simply to achieve acceptable performance for distributed applications, many researchers have proposed techniques to perform this tuning automatically. This paper first discusses the relative merits of the various approaches in theory, and then provides substantial experimental data concerning two competing implementations-the buffer autotuning already present in Linux 2.4.x and "dynamic right-sizing." The paper reveals heretofore unknown aspects of the problem and current solutions, provides insight into the proper approach for different circumstances, and points toward ways to further improve performance.