Scalability vs. Performance

Abstract

In the ideal world, the performance of a program running on a supercomputer would always be proportional to the peak speed of the system being used. Furthermore, the program would always achieve a high percentage of peak (e.g., 50% or better). In the real world, this is frequently not the case. Therefore, it is important to distinguish between the following five concepts: (1) performance (run time), (2) ideal speedup, (3) hard scalability (fixed problem size speedup), (4) soft scalability (scaled speedup), and (5) throughput (how long it takes to run a collection of jobs). This report addresses these concepts and explains their meanings and differences. Hopefully, this will allow readers to evaluate the behavior of programs and computer systems, and most importantly, to evaluate their own expectations for running a program on a particular system or class of systems. Examples, which demonstrate these concepts, are drawn from a variety of projects and include both problems from multiple computational technology areas (CTAs) and results from outside of the Department of Defense (DOD). In some cases, there will also be theoretical arguments to help better explain the issues.

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Document Details

Document Type
Technical Report
Publication Date
Sep 01, 2001
Accession Number
ADA396422

Entities

People

  • Daniel M. Pressel

Organizations

  • United States Army Research Laboratory

Tags

DTIC Thesaurus Topics

  • Air Force
  • Algorithms
  • Computational Fluid Dynamics
  • Computer Architecture
  • Computer Programming
  • Computers
  • Data Sets
  • Department Of Defense
  • Fluid Dynamics
  • High Performance Computing
  • Information Science
  • Instruction Set Architecture
  • Materials Science
  • Military Research
  • Parallel Computing
  • Scalability
  • Throughput

Fields of Study

  • Computer science

Readers

  • Computational Fluid Dynamics (CFD)
  • Computational Modeling and Simulation
  • Systems Analysis and Design