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Threshold value calculation to determine critical functions in code

Vasudev_J_
Beginner
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One perameter to mark critical function is high CPI, But what are the other perameters to determine that? Specifically in the general exploration result from vtune, in the given formula (when i hovered on pink color CPI):

Threshold: (CPU_CLK_UNHALTED.THREAD / INST_RETIRED.ANY > 1) * (CPU_CLK_UNHALTED.THREAD / > 0.05)

What is this second part (in bold italic). How vtune marks pink color for some CPI values.

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David_A_Intel1
Employee
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Hi Vasudev,

Great question!  The threshold basically says that the function account for great than 5% of all clockticks (i.e., CPU_CLK_UNHALTED.THREAD) collected during the run.  That is, the function must contribute more than 5% of all the time spent executing the application.

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David_A_Intel1
Employee
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BTW, if you don't like that threshold, you can create your own metrics!  See the User Metrics sdk in C:\Program Files (x86)\Intel\VTune Amplifier XE 2013\sdk\user_metrics (for Windows*) and /opt/intel/vtune_amplifier_xe/sdk/user_metrics (for Linux*), by default.

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Vasudev_J_
Beginner
305 Views

Thanks MrAnderson.:)

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