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How basic hotspot analysis is different from advance hotspot analyis

Ayam
Beginner
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I run the application on intel vtune to extract the information about the functions that are consuming most of the time. Same application running with the basic hotspot analysis and advance hotspot analysis are indicating different functions. Can you please explain me what is the difference between these analyzers and what could be the reason for this behavior. 

Thanks you

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David_A_Intel1
Employee
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Hello Ayam:

Basic Hotspots is software-based sampling with a default resolution of 10 ms.  Advanced Hotspots is hardware-based sampling with a default resolution of 1 ms.  This resolution difference could account for the difference you are seeing.  However, note, you need to collect samples for a significant amount of time in order for the "sampling" to be representative of what is happening.  Collecting data for only 1 or 2 seconds will result in various results from run to run.

Also note that various controls on the bottom of the page affect how the data is displayed.  For example, the "Call Stack Mode" causes time dat to be aggregated to either the user function, user function plus one level down, or user and system functions.  Ensure that you are using the same mode in both results displays.

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Bernard
Valued Contributor I
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As a additional note to what MrAnderson said your sampled code execution time should be more than two full sample period. That's mean more that 2 msec.

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Ayam
Beginner
463 Views

thanks a lot for the explanation.

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Bernard
Valued Contributor I
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You are welcome.

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