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Is there a way to show the reliability of the metrics in CLI ?

martinyyyy
Beginner
748 Views

Hi,

 

Good day to you.

 

I notice that some cells are grey in the bottom-up window which read: This metric cannot be reliably calculated due to multiplexing issues or a low number of collected PMU samples. 

 

I want to know if I can get this result from the command-line interface. There are lines in the hotspots report that are unreliable which I can, but some are not so obvious. It would be a waste of time to check manually one by one using the GUI interface. What's the threshold of a low number of collected PMU samples?

 

Regards,

Martin

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3 Replies
Jeffrey_R_Intel1
Employee
677 Views

Hello Martin,


The online documentation for this issue is available at https://www.intel.com/content/www/us/en/develop/documentation/vtune-help/top/troubleshooting/wrong-event-count-with-event-multiplexing.html and https://www.intel.com/content/www/us/en/develop/documentation/vtune-help/top/analyze-performance/hw-event-based-sampling-collection/allow-multiple-runs-or-multiplex-events.html


Basically, the number of PMU hardware events VTune data collectors can monitor during a single run is limited by the processor, so VTune can "multiplex" the collection of multiple counters. The workaround when you experience this issue is to allow multiple runs (-allow-multiple-runs command line argument and "Allow multiple runs" GUI checkbox in the What -> Advanced pane).


To see the threshold for each event, in the GUI, expand the Details view in the How pane and scroll down to the "Events configured for CPU: ..." section where the events and "Sample After" values are listed. The sample after values are the counts that are triggering this message.


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Jeffrey_R_Intel1
Employee
654 Views

Hello Martin,

Did the previous post answer your question? Can I close this issue?

Thank you.


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Jeffrey_R_Intel1
Employee
635 Views

Hello Martin,

I am closing this issue, so Intel will no longer be tracking it.

Thank you.


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