Method and system for selecting instrumentation points in a computer program ...

United States Patent m

Vogel

[54] METHOD AND SYSTEM FOR SELECTING INSTRUMENTATION POINTS IN A COMPUTER PROGRAM

[75] Inventor: Keith Randel Vogel, Duvall. Wash.

[73] Assignee: Microsoft Corporation, Redmond.
Wash.

[21] Appl. No.: 268,444
[22] Filed: Jun. 30,1994

[51] IntCl.6 G06F9/44

[52] U.S. CI 395/704; 395/183.11

[58] Field of Search 371/16. 19; 395/700,

395/704. 183.11. 183.14

[56] References Cited

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3,427,443 2/1969 Apple et al 371/19 X

3,551,659 12/1970 Fotsythe 371/19 X

4,819,233 4/1989 DeLuciaetal 371/19

OTHER PUBLICATIONS

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James R. Larus et al., "Rewriting Executable Files to Measure Program Behavior," University of Wisconsin Computer Sciences Technical Report 108S, 1992. pp. 1-17. Thomas Ball et al.. "Optimally Profiling and Tracing Programs," University of Wisconsin Computer Sciences Technical Report 1031, 1991. pp. 1-27. Vivek Sarkar, "Determining Average Program Execution Times and their Variance," Proceedings of SIGPLAN '89 Conference on Programming Language Design and Implementation, SIGPLAN Notices, vol. 24. No. 7. Jul. 1989. pp. 298-312.

Karl Pettis et al. "Profile Guided Code Positioning," Proceedings of the ACM SIGPLAN '90 Conference on Programming Language Design and Implementation, Jun. 20-22. 1990, pp. 16-27.

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US005790858A [ii] Patent Number: 5,790,858 [45] Date of Patent: Aug. 4, 1998

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Primary Examiner—Emanuel T. Voeltz

Assistant Examiner—Kakali Chaki

Attorney, Agent, or Firm—Seed and Berry LLP

[57] ABSTRACT

The present invention provides a method in a computer system for selecting instrumentation points in a computer program. Instrumentation points are locations within the computer program at which instrumentation code is inserted. The method includes identifying code portions such as basic blocks in the computer program code, creating a control flow graph out of the code portions, generating a spanning tree for the control flow graph, and then selecting those edges of the control flow graph which are not a part of the spanning tree as instrumentation points. After instrumentation points are selected, instrumentation code may be added at those locations. When the computer program is executed, the added instrumentation code records execution information such as how many times an instrumentation point is accessed during execution of the computer program. Using the recorded execution information and direction specified in the control flow graph, execution information for the non-instrumented blocks may then be calculated.

9 Claims, 11 Drawing Sheets