Introduction Real-time systems and many other computer applications must meet specifications and perform tasks that satisfy timing as well as logical criteria for correctness. Examples of timing properties and constraints include deadlines, the periodic execution of processes, and external event recognition based on time of occurrence (e.g., [9, 18]). We present a scheme for reasoning with and about time and for specifying timing properties in concurrent programs. The objectives are to predict the tim1 This chapter is based on "Reasoning about Time in Higher-Level Language Software," by Alan Shaw that appeared in IEEE Transactions on Software Engineering, vol. 15, no. 7, pp. 875--889, July 1989, c fl1989 IEEE. Sec. 16.1 Introduction 375 ing behavior of higher-level language programs and to prove that they meet their timing constraints, through the direct analysis of program statements. Timing

An analytical performance model for parallel programs can provide qualitative insight as well as efficient quantitative evaluation and prediction of parallel program performance. While stochastic models for parallel programs can represent execution time variance due to communication and resource contention delays, a qualitative assessment of previous models shows that the stochastic assumption makes it extremely difficult to compute synchronization costs and overall execution times. This thesis first re-evaluates the need for the stochastic assumption by examining the influence of non-deterministic communication and resource contention delays on execution times in parallel programs. An analytical model of program behavior, combined with detailed program measurements, provides compelling evidence that in shared-memory programs on current systems as well as programs with similar granularity on foreseeable future systems, such delays introduce extremely low variance into the execution tim...

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A technique is described to automatically compile performance models in the course of program translation. The performance models are fully symbolic in order to preserve as much diagnostic information as possible. Although compiled statically, the models account for the effects of resource contention, due to the introduction of a novel algorithm within the symbolic compilation scheme. It is shown that the compilation approach fundamentally outperforms traditional static estimation procedures in terms of precision at a negligible increase in cost. This claim is illustrated by a case study of an LU factorization algorithm on a multiprocessor. 1 Introduction Low-cost, compile-time performance prediction provides essential, early feedback to enable program and machine parameter optimization by both the user and the compiler. In this paper we present a technique to automatically compile a symbolic performance model which accurately predicts the execution time of a parallel program given a...

While last year's report [16] loosely introduced the general concepts behind the Pamela approach toward modeling and analysis of parallel systems, this report exclusively focuses on the calculus of the methodology. In particular, it defines an algorithmic approach toward serialization analysis, which enables (future) mechanization of the analysis. Thus, a technique is developed to automatically compile symbolic performance models in the course of program translation. It is shown that the resulting performance models fundamentally outperform traditional static estimation approaches at a negligible increase in cost. This claim is illustrated by two case studies, i.e., an LU factorization algorithm on a multiprocessor, and a matrix-vector update on a multicomputer. Contents 1 Introduction 2 2 Analysis 5 2.1 Mathematical Preliminaries : : : : : : : : : : : : : : : : : : : : : 5 2.2 Formalism : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 7 2.3 Homomorphic Mapping : : : :...

In this document we propose a symbolic performance modeling technique to be used as the basis of the JOSES cost estimator. The approach is inspired by the need for highly parametric cost models in the initial stages in parallel program design, where absolute prediction accuracy is of less priority than solution cost, and where symbolic feedback on the effects of user mapping decisions and machine parameters is of primary concern. As illustrated by the case study, the symbolic approach provides good feedback on the effects of partitioning choices as well as the influence of computation and communication parameters on application performance.