Evaluating computing system changes by means of regression models

ABSTRACT

This paper describes how a regression model of the Research Center's APL system was constructed and used for evaluating system changes. The regression methodology that is generally used for performing such an analysis is believed to have been expanded by the introduction of multiple regression equations for estimating the cumulative distribution function of a performance variable. A model is developed which shows that the size of the workspace, but not the number of workspaces in core, significantly affects the performance of the Research Center's system. In particular, the model indicates that increasing the workspace size from 5 to 7 tracks causes 11 percent of all requests to be degraded by at least 0.4 seconds under mean load conditions.

REFERENCES

• 1: Waldbaum, G., "Large Capacity Storage and Time Sharing System/360", IBM RC 2698, November 11, 1969
• 2: Watson, R., "Computer Performance Analysis: Applications of Accounting Data", RAND Report R-573-NASA/PR, May 1971
• 3: Bard, Y., "Performance Criteria and Measurement for a Time-Sharing System", IBM Systems Journal, Vol. 10, No. 3, pp 193-216, 1971
• 4: Silverman, H. F. and Yue, P. C., "The Response Time Characterization of an Information Retrieval System", IBM RC 3796, March 30, 1972
• 5: "APL/360-OS and APL/360-DOS General Information Manual", IBM Corporation, GH20-0850
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INDEX TERMS

Primary Classification:
  G. Mathematics of Computing
  G.3 PROBABILITY AND STATISTICS
      Subjects: Correlation and regression analysis

Additional Classification:
  D. Software
  D.3 PROGRAMMING LANGUAGES
      D.3.2 Language Classifications

          Nouns: APL

  G. Mathematics of Computing
  G.3 PROBABILITY AND STATISTICS
      Subjects: Distribution functions

  I. Computing Methodologies
  I.6 SIMULATION AND MODELING
      I.6.5 Model Development

General Terms:
Performance, Theory