We describe a binding schema markup language (BSML) for describing data interchange between scientific codes. Such a facility is an important constituent of scientific problem solving environments (PSEs). BSML is designed to integrate with a PSE or application composition system that views model specification and execution as a problem of managing semistructured data. The data interchange problem is addressed by three techniques for processing semistructured data: validation, binding, and conversion. We present BSML and describe its application to a PSE for wireless communications system design.

Alex Verstak

Naren Ramakrishnan

Layne T. Watson

Jian He

Clifford A. Shaffer

Kyung Kyoon Bae

Jing Jiang

William H. Tranter

Theodore S. Rappaport

BSML: A Binding Schema Markup Language for Data Interchange in Problem Solving Environments

Current performance prediction analytical models try to characterize the performance behavior of actual machines through a small set of parameters. In practice, substantial deviations are observed. These differences are due to factors as memory hierarchies or network latency. A natural approach is to associate a different proportionality constant with each basic block, and analogously, to associate different latencies and bandwidths with each &#x22;communication block&#x22;. Unfortunately, to use this approach implies that the evaluation of parameters must be done for each algorithm. This is a heavy task, implying experiment design, timing, statistics, pattern recognition and multi-parameter fitting algorithms. Software support is required. We present a compiler that takes as source a C program annotated with complexity formulas and produces as output an instrumented code. The trace files obtained from the execution of the resulting code are analyzed with an interactive interpreter, giving us, among other information, the values of those parameters.

J.A. Gonz&#xe1;lez

C. Rodr&#xed;guez

G. Rodr&#xed;guez

F. de Sande

M. Printista

A Tool for Performance Modeling of Parallel Programs

In this paper we describe the extension of the CAPO parallelization support tool to support multilevel parallelism based on OpenMP directives. CAPO generates OpenMP directives with extensions supported by the NanosCompiler to allow for directive nesting and definition of thread groups. We report some results for several benchmark codes and one full application that have been parallelized using our system.

Haoqiang Jin

Gabriele Jost

Jerry Yan

Eduard Ayguade

Marc Gonzalez

Xavier Martorell

Automatic Multilevel Parallelization Using OpenMP

A performance-prediction model is presented, which describes different hierarchical workload decomposition strategies for particle in cell (PIC) codes on Clusters of Symmetric MultiProcessors. The devised workload decomposition is hierarchically structured: a higher-level decomposition among the computational nodes, and a lower-level one among the processors of each computational node. Several decomposition strategies are evaluated by means of the prediction model, with respect to the memory occupancy, the parallelization efficiency and the required programming effort. Such strategies have been implemented by integrating the high-level languages High Performance Fortran (at the inter-node stage) and OpenMP (at the intra-node one). The details of these implementations are presented, and the experimental values of parallelization efficiency are compared with the predicted results.

Sergio Briguglio

Beniamino Di Martino

Gregorio Vlad

A Performance-Prediction Model for PIC Applications on Clusters of Symmetric MultiProcessors: Validation with Hierarchical HPF+OpenMP Implementation

In this paper we explore the idea of customizing and reusing loop schedules to improve the scalability of non-regular numerical codes in shared-memory architectures with non-uniform memory access latency. The main objective is to implicitly setup affinity links between threads and data, by devising loop schedules that achieve balanced work distribution within irregular data spaces and reusing them as much as possible along the execution of the program for better memory access locality. This transformation provides a great deal of flexibility in optimizing locality, without compromising the simplicity of the shared-memory programming paradigm. In particular, the programmer does not need to explicitly distribute data between processors. The paper presents practical examples from real applications and experiments showing the efficiency of the approach.

Dimitrios S. Nikolopoulos

Ernest Artiaga

Eduard Ayguad&#xe9;

Jes&#xfa;s Labarta

Scaling Non-Regular Shared-Memory Codes by Reusing Custom Loop Schedules

In this work, we present an OpenMP implementation suitable for multiprogrammed environments on Intel-based SMP systems. This implementation consists of a runtime system and a resource manager, while we use the NanosCompiler to transform OpenMP-coded applications into code with calls to our runtime system. The resource manager acts as the operating system scheduler for the applications built with our runtime system. It executes a custom made scheduling policy to distribute the available physical processors to the active applications. The runtime system cooperates with the resource manager in order to adapt each application's generated parallelism to the number of processors allocated to it, according to the resource manager scheduling policy. We use the OpenMP version of the NAS Parallel Benchmark suite in order to evaluate the performance of our implementation. In our experiments we compare the performance of our implementation with that of a commercial OpenMP implementation. The comparison proves that our approach performs better both on a dedicated and on a heavily multiprogrammed environment.

Vasileios K. Barekas

Panagiotis E. Hadjidoukas

Eleftherios D. Polychronopoulos

Theodore S. Papatheodorou

A Multiprogramming Aware OpenMP Implementation

The purpose of this benchmark is to propose several optimization techniques and to test their existence in current OpenMP compilers. Examples are the removal of redundant synchronization constructs, effective constructs for alternative code and orphaned directives. The effectiveness of the compiler generated code is measured by comparing different OpenMP constructs and compilers. If possible, we also compare with the hand coded &#x22;equivalent&#x22; solution. Six out of seven proposed optimization techniques are already implemented in different compilers. However, most compilers implement only one or two of them.

Matthias S. M&#xfc;ller

An OpenMP Compiler Benchmark

Ronald Perrott

Boleslaw Szymanski

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Scientific Programming provides a forum for research results in, and practical experience with, software engineering environments, tools, languages, and models of computation aimed specifically at supporting scientific and engineering computing.

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Chief Editor&nbsp;Professor Tramontana&nbsp;is based at the University of Catania and his research primarily concerns the areas of software engineering and distributed systems.

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Scientific Programming - Table of contents 2003

title

Scientific Programming provides a forum for research results in, and practical experience with, software engineering environments, tools, languages, and models of computation aimed specifically at supporting scientific and engineering computing.

Scientific Programming