Aad J. van der Steen

The International Exascale Software Project roadmap

Over the last 20 years, the open-source community has provided more and more software on which the world’s high-performance computing systems depend for performance and productivity. The community has invested millions of dollars and years of effort to build key components. However, although the investments in these separate software elements have been tremendously valuable, a great deal of productivity has also been lost because of the lack of planning, coordination, and key integration of technologies necessary to make them work together smoothly and efficiently, both within individual petascale systems and between different systems. It seems clear that this completely uncoordinated development model will not provide the software needed to support the unprecedented parallelism required for peta/ exascale computation on millions of cores, or the flexibility required to exploit new hardware models and features, such as transactional memory, speculative execution, and graphics processing units. This report describes the work of the community to prepare for the challenges of exascale computing, ultimately combing their efforts in a coordinated International Exascale Software Project.

The distributed ASCI Supercomputer project

The Distributed ASCI Supercomputer (DAS) is a homogeneous wide-area distributed system consisting of four cluster computers at different locations. DAS has been used for research on communication software, parallel languages and programming systems, schedulers, parallel applications, and distributed applications. The paper gives a preview of the most interesting research results obtained so far in the DAS project.

An Evaluation of Some Beowulf Clusters

We report the results of an evaluation project on three Beowulf type clusters. The purpose of this study was to assess both the performance of the clusters and the availability and quality of the software for cluster management and management of the available resources. This last goal could hardly be achieved because at the time this project was undertaken much of the management software was either very immature or not yet available. However, it was possible to assess the cluster performance both from the point of view of single program execution as well as with respect to throughput by loading the systems according to a predefined schedule via the available batch systems. To this end a set of application programs, ranging from astronomy to quantum chemistry, together with a synthetic benchmark were employed. From the results we wanted to derive answers about the viability of using cluster systems routinely in a multi-user environment with comparable maintenance cost and effort to that of an integrated parallel machine.We report the results of an evaluation project on three Beowulf type clusters. The purpose of this study was to assess both the performance of the clusters and the availability and quality of the software for cluster management and management of the available resources. This last goal could hardly be achieved because at the time this project was undertaken much of the management software was either very immature or not yet available. However, it was possible to assess the cluster performance both from the point of view of single program execution as well as with respect to throughput by loading the systems according to a predefined schedule via the available batch systems. To this end a set of application programs, ranging from astronomy to quantum chemistry, together with a synthetic benchmark were employed. From the results we wanted to derive answers about the viability of using cluster systems routinely in a multi-user environment with comparable maintenance cost and effort to that of an integrated parallel machine.

A parallel data assimilation model for oceanographic observations

In this paper we describe the development of a program that aims at achieving the optimal integration of observed data in an oceanographic model describing the water transport phenomena in the Agulhas area at the tip of South Africa. Two parallel implementations, MPI and OpenMP, are described and experiments with respect to speed and scalability on a Compaq AlphaServer SC and an SGI Origin3000 are reported. Copyright

A Performance Analysis of the SGI Origin2000

In this paper we present the results of benchmark experiments carried out on a Silicon Graphics Origin2000. We used the three modules of the EuroBen Benchmark ([1]) to assess the performance of a single node, as a shared memory system, and as a distributed memory system. Where the situation calls for it, we compare the results with those obtained on a Cray T3E and an IBM SP2. The results obtained from this benchmark give a good impression of what performances can be attained on the Origin2000 under what circumstances and expose the weak and strong points of the system.

A Fully Implicit Parallel Ocean Model Using MUMPS

The formulation, implementation and performance of a new fully implicit parallel model of the ocean circulation is presented. Within this model, steady states can be traced in one of the control parameters. In addition, transient flows can be computed using relatively (compared to traditional ocean models) large time steps such that long integration times can be reached. The discretized equations of the ocean model are solved by the Newton-Raphson technique and the emerging linear systems are solved by a (MPI) version of the MUltifrontal Massively Parallel Solver. The performance of the code on an SGI Origin 2000 platform is presented here using typical results for a sector ocean flow.

Simulation of Scientific Programs on Parallel Architectures

In this paper a method is presented to model and simulate scientific application that are implemented as SPMD programs with message-passing. This method is based on the counting of basic operations and the recognition of known kernels. A Fortran analyzer was built to generate automatically a model of such an application for the simulation tool of the MIMESIS project, developed at EDF (Electricite de France). Models of distributed-memory computers, employing this model description, were implemented within the prototype of the project. The approach was validated with two EDF codes, for which the simulations gave good results.