Scientific Programming - Volume 10, issue 1

Authors: Gerndt, Michael

Article Type: Other

Citation: Scientific Programming, vol. 10, no. 1, pp. 1-2, 2002

Authors: Hey, Tony | Papay, Juri

Article Type: Research Article

Abstract: Performance Engineering is concerned with the reliable prediction and estimation of the performance of scientific and engineering applications on a variety of parallel and distributed hardware. This paper reviews the present state of the art in 'Performance Engineering' for both parallel computing and meta-computing environments and attempts to look forward to the application of these techniques in the wider context of Problem Solving Environments and the Grid. The paper compares various techniques such as benchmarking, performance …measurements, analytical modelling and simulation, and highlights the lessons learned in the related projects. The paper concludes with a discussion of the challenges of extending such methodologies to computational Grid environments. Show more

Citation: Scientific Programming, vol. 10, no. 1, pp. 3-17, 2002

Authors: Moreira, José E. | Midkiff, Samuel P. | Gupta, Manish | Wu, Peng | Almasi, George | Artigas, Pedro

Article Type: Research Article

Abstract: When Java was first introduced, there was a perception that its many benefits came at a significant performance cost. In the particularly performance-sensitive field of numerical computing, initial measurements indicated a hundred-fold performance disadvantage between Java and more established languages such as Fortran and C. Although much progress has been made, and Java now can be competitive with C/C++ in many important situations, significant performance challenges remain. Existing Java virtual machines are …not yet capable of performing the advanced loop transformations and automatic parallelization that are now common in state-of-the-art Fortran compilers. Java also has difficulties in implementing complex arithmetic efficiently. These performance deficiencies can be attacked with a combination of class libraries ({\it packages}, in Java) that implement truly multidimensional arrays and complex numbers, and new compiler techniques that exploit the properties of these class libraries to enable other, more conventional, optimizations. Two compiler techniques, {\it versioning} and {\it semantic expansion}, can be leveraged to allow fully automatic optimization and parallelization of Java code. Our measurements with the NINJA prototype Java environment show that Java can be competitive in performance with highly optimized and tuned Fortran code. Show more

Citation: Scientific Programming, vol. 10, no. 1, pp. 19-33, 2002

Authors: César, Eduardo | Morajko, Anna | Margalef, Tomàs | Sorribes, Joan | Espinosa, Antonio | Luque, Emilio

Article Type: Research Article

Abstract: Performance analysis and tuning of parallel/distributed applications are very difficult tasks for non-expert programmers. It is necessary to provide tools that automatically carry out these tasks. These can be static tools that carry out the analysis on a post-mortem phase or can tune the application on the fly. Both kind of tools have their target applications. Static automatic analysis tools are suitable for stable application while dynamic tuning tools are more appropriate to applications with dynamic …behaviour. In this paper, we describe KappaPi as an example of a static automatic performance analysis tool, and also a general environment based on parallel patterns for developing and dynamically tuning parallel/distributed applications. Show more

Citation: Scientific Programming, vol. 10, no. 1, pp. 35-44, 2002

Authors: Tao, Jie | Karl, Wolfgang | Schulz, Martin

Article Type: Research Article

Abstract: Shared memory applications running transparently on top of NUMA architectures often face severe performance problems due to bad data locality and excessive remote memory accesses. Optimizations with respect to data locality are therefore necessary, but require a fundamental understanding of an application's memory access behavior. The information necessary for this cannot be obtained using simple code instrumentation due to the implicit nature of the communication handled by the NUMA hardware, the large amount of traffic …produced at runtime, and the fine access granularity in shared memory codes. In this paper an approach to overcome these problems and thereby to enable an easy and efficient optimization process is presented. Based on a low-level hardware monitoring facility in coordination with a comprehensive visualization tool, it enables the generation of memory access histograms capable of showing all memory accesses across the complete address space of an application's working set. This information can be used to identify access hot spots, to understand the dynamic behavior of shared memory applications, and to optimize applications using an application specific data layout resulting in significant performance improvements. Show more

Citation: Scientific Programming, vol. 10, no. 1, pp. 45-53, 2002

Authors: Reussner, Ralf | Sanders, Peter | Träff, Jesper Larsson

Article Type: Research Article

Abstract: The main objective of the MPI communication library is to enable {\it portable parallel programming} with high performance within the message-passing paradigm. Since the MPI standard has no associated performance model, and makes no performance guarantees, comprehensive, detailed and accurate performance figures for different hardware platforms and MPI implementations are important for the application programmer, both for understanding and possibly improving the behavior of a given program on a given platform, as …well as for assuring a degree of predictable behavior when switching to another hardware platform and/or MPI implementation. We term this latter goal {\it performance portability}, and address the problem of attaining performance portability by benchmarking. We describe the SKaMPI benchmark which covers a large fraction of MPI, and incorporates well-accepted mechanisms for ensuring accuracy and reliability. SKaMPI is distinguished among other MPI benchmarks by an effort to maintain a public performance database with performance data from different hardware platforms and MPI implementations. Show more

Citation: Scientific Programming, vol. 10, no. 1, pp. 55-65, 2002

Authors: Rackl, Günther | Ludwig, Thomas | Lindermeier, Markus | Stamatakis, Alexandros

Article Type: Research Article

Abstract: Software development is getting more and more complex, especially within distributed middleware-based environments. A major drawback during the overall software development process is the lack of on-line tools, i.e. tools applied as soon as there is a running prototype of an application. The MIMO MIddleware MOnitor provides a solution to this problem by implementing a framework for an efficient development of on-line tools. This paper presents a methodology for developing on-line tools with MIMO. As …an example scenario, we choose a distributed medical image reconstruction application, which represents a test case with high performance requirements. Our distributed, CORBA-based application is instrumented for being observed with MIMO and related tools. Additionally, load balancing mechanisms are integrated for further performance improvements. As a result, we obtain an integrated tool environment for observing and steering the image reconstruction application. By using our rapid tool development process, the integration of on-line tools shows to be very convenient and enables an efficient tool deployment. Show more

Citation: Scientific Programming, vol. 10, no. 1, pp. 67-74, 2002

Authors: Iyengar, Arun | Rosu, Daniela

Article Type: Research Article

Abstract: Web site applications are some of the most challenging high-performance applications currently being developed and deployed. The challenges emerge from the specific combination of high variability in workload characteristics and of high performance demands regarding the service level, scalability, availability, and costs. In recent years, a large body of research has addressed the Web site application domain, and a host of innovative software and hardware solutions have been proposed and deployed. This paper is …an overview of recent solutions concerning the architectures and the software infrastructures used in building Web site applications. The presentation emphasizes three of the main functions in a complex Web site: the processing of client requests, the control of service levels, and the interaction with remote network caches. Show more

Citation: Scientific Programming, vol. 10, no. 1, pp. 75-89, 2002

Authors: Moreau, Luc | Ribbens, Daniel

Article Type: Research Article

Abstract: {\it Mobile Objects in Java} provides support for object mobility in Java. Similarly to the RMI technique, a notion of client-side stub, called startpoint, is used to communicate transparently with a server-side stub, called endpoint. Objects and associated endpoints are allowed to migrate. Our approach takes care of routing method calls using an algorithm that we studied in. The purpose of this paper is to present and evaluate the implementation of this algorithm in Java. In …particular, two different strategies for routing method invocations are investigated, namely {\it call forwarding} and {\it referrals}. The result of our experimentation shows that the latter can be more efficient by up to 19%. Show more

Citation: Scientific Programming, vol. 10, no. 1, pp. 91-100, 2002