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milliseconds vs clockticks

lionel-vtune
Beginner
199 Views
I've been using VTune to monitor the clockticks of various functions in order to do some performance tuning. I'd now like to time the functions but I'm confused as to how to interpret the results portrayed by VTune. I can change the sampling from event to OS timer, run the analysis, drill downand see the bar graph info for the various functions, but I can't see anywhere on the screen where it lists the actual milliseconds used for each function. Where is this information displayed? Thanks in advance everyone!
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David_A_Intel1
Employee
199 Views

Lionel:

You need to use Call Graph to get function timing information. Sampling is only statistical analysis. It represents the relative activity of the code. It does not report actual timing information, regardless of the mechanism used to collect the samples.

Call graph, however, can report function timings, since the code is instrumented to collect this information. However, it is still not 100% accurate, since there is overhead in the calculations. This is taken into account, but cannot be 100% accurate.
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