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Standard Performance Evaluation Corporation


CPU95 Timing Patch
For Use on Microsoft Operating Systems

Date: Fri Apr 21 13:05:32 EDT 2000

Timing information for measuring the runtime of the SPEC CPU95 benchmarks is obtained by reading the operating system's timer and obtaining two items:

  • The total number of seconds
  • The fractional portion of seconds

On Microsoft operating systems, the SPEC CPU95 (Version 1.0 and 1.1) tools interpret the fractional portion of seconds as microseconds when the value should be interpreted as milliseconds. SPEC has released a patch to correct this problem.

Implications: The current interpretation by the SPEC CPU95 tools (Version 1.0 and 1.1) can lead to the reported time being, at most, .998 seconds from the actual time, with an average approaching ~.5 seconds. SPEC has checked and reprocessed all results submitted to SPEC on Microsoft operating systems and has found ~1% or less variation in calculated results for results submitted to SPEC as of April 1, 2000. SPEC is notifying licensees of the availability of this patch and ensuring that submissions for the SPEC website are processed with the fractional time interpreted correctly.

Download the patch!

Patch directions (requires SPEC CPU95 to be already installed):

  1. Set your directory to the top of your SPEC CPU95 directory tree
  2. Set your SPEC environment variable
  3. Unzip the patch file
  4. Execute the file "patch1.bat"