Profiling (computer programming): Difference between revisions

Revision as of 21:13, 20 December 2005

Revision as of 12:15, 24 December 2005

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Some profilers instrument the target program with additional instructions to collect the required information. Instrumenting the program can cause changes in the performance of the program, causing inaccurate results and [[heisenbug]]s. Instrumenting can potentially be very specific but slows down the target program as more specific information is collected.

The resulting data isare not exact, but a statistical approximation. ''The actual amount of error is usually more than one sampling period. In fact, if a value is n times the sampling period, the expected error in it is the square-root of n sampling periods.'' [http://lgl.epfl.ch/teaching/case_tools/doc/gprof/gprof_12.html]

Two of the most commonly used statistical profilers are [[GNU]]'s gprof and [[Silicon Graphics|SGI]]'s Pixie.