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This paper provides an overview of commercial applications of Grid computing. We discuss Web performance and present a Grid caching architecture. Our Grid caching architecture offloads requests to Grid caches when Web servers become overloaded. We describe performance and traffic modeling techniques which can enhance Grid applications such as caching. We also discuss how Grid computing can be applied...
This paper describes the concept of optimistic grid computing. This allows applications to synchronize more loosely and better tolerate the dynamic and heterogeneous bandwidths and latencies that are seen in grid environments. Based on the observed performance of a world-wide grid testbed, we estimate target operating regions for grid applications. Mesh generation is the primary test application where...
Mobile agents provide an important paradigm for supporting dynamic services in Computational Grids. We outline reasons why mobile agents are useful and how they can provide support for resource discovery and performance management in the context of service-oriented Grids. We also discuss factors which are likely to limit the uptake of the mobile agent approach, and how some of these restrictions can...
This paper presents the OCM-G, a Grid application monitoring system. The OCM-G is aimed to provide services via which tools supporting application development are enabled to gather information, manipulate, and detect events that occur when applications are running. The functionality of the OCM-G is available via a standardized interface, On-line Monitoring Interface Specification (OMIS). The OCM-G...
UNICORE (Uniform Interface to Computer Resources) is a software infrastructure to support seamless and secure access to distributed resources. It has been developed by the projects UNICORE and UNICORE Plus in 1997 – 2002 (funded by the German Ministry of Education and Research) and is going to be enhanced in the EU-funded projects EUROGRID and GRIP. The UNICORE system allows uniform access to different...
Parallel computing is a promising approach that provides more powerful computing capabilities for many scientific research fields to solve new problems. However, to take advantage of such capabilities it is necessary to ensure that the applications are successfully designed and that their performance is satisfactory. This implies that the task of the application designer does not finish when the application...
In this work we present a performance model that encompasses the key characteristics of a Sn transport application using unstructured meshes. Sn transport is an important part of the ASCI workload. This builds on previous analysis which has been done for the case of structured meshes. The performance modeling of an unstructured grid application presents a number of complexities and subtleties that...
The efficiency of modern microprocessors is extremely sensitive towards the structure and memory access pattern of programs to be executed. This is caused by memory hierarchies which were introduced to reduce average memory access times. In this paper, we consider embedded Runge-Kutta (RK) methods for the solution of ordinary differential equations arising from space discretization problems for partial...
With the trend in the supercomputing world shifting from homogeneous machine architectures to hybrid clusters of SMP nodes, the interoperabiility of OpenMP and MPI has become a key issue in understanding and optimizing the overall system performance. While the low-level performance of MPI and OpenMP can be evaluated using existing benchmarks, the combination of the two poses new challenges. Therefore,...
Many applications from scientific computing and physical simulations can benefit from a mixed task and data parallel implementation on parallel machines with a distributed memory organization, but it may also be the case that a pure data parallel implementation leads to faster execution times. Since the effort for writing a mixed task and data parallel implementation is large, it would be useful to...
The efficient implementation of collective communication is a key factor to provide good performance and scalability of communication patterns that involve global data movement and global control. Moreover, this is essential to enhance the fault-tolerance of a parallel computer. For instance, to check the status of the nodes, perform some distributed algorithm to balance the load, synchronize the...
A major method of constructing applications to run on a computational Grid is to assemble them from components — separately deployable units of computation of well-defined functionality. Performance steering is an adaptive process involving run-time adjustment of factors affecting the performance of an application. This paper presents a design for a system capable of steering, towards a minimum run-time,...
To address the increasing complexity in parallel and distributed systems and software, advances in performance technology towards more robust tools and broader, more portable implementations are needed. In doing so, new challenges for performance instrumentation, measurement, analysis, and visualization arise to address evolving requirements for how performance phenomena is observed and how performance...
Computing environments continue to increase in scale, heterogeneity, and hierarchy, with resource usage varying dynamically during program execution. Computational and data grids and distributed collaboration environments are examples. To understand performance and gain insights into developing applications that efficiently use the system resources, performance visualization has proven useful. However,...
The paper presents the main features of a performance analysis tool for applications running on the Grid, which is not limited to standard measurements, but also comprises application-specific metrics and other high-level measurements. These requirements are not well addressed by the existing tools in the area of parallel and distributed programming. The paper outlines the main ideas as well as the...
Dynamic instrumentation, meaning modification of an application’s instructions at run-time in order to monitor its behaviour, is a very powerful foundation for a wide range of program manipulation tools. This paper concerns the problem of implementing dynamic instrumentation for a managed run-time environment such as a Java Virtual Machine (JVM). We present a flexible new approach based on a “virtual”...
Aksum is a multi-experiment performance analysis tool for message passing, shared memory and mixed parallelism programs; it automatically instruments the user’s application, generates versions of this application using a set of user-supplied input parameters, collect the data generated by the instrumentation and analyzes it, relates the performance problems back to the source code, and compares the...
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