Vtune timing consistency of hotspots

[Srihari_S]

Hi. I was trying to run the vtune profiler multiple times for an application. I was trying to check on the hotspots. The hotspots were given with their % of timing and time taken(in ms). I ran the application multiple times and analysed the timing of functions. I could see variation in the time taken by the function in 5 observations [ 0.169, 0.172, 0.250, 0.350, 0.342] ( observations not neccessarily in the same order and are given in ms). Is this expected behaviour. Kindly share your thoughts

[RemyaP_Intel]

Hi,

Thank you for posting in Intel communities.

The timing of the functions given are in ms and a slight variation in the time taken for analysis is expected. 

If you are trying to estimate the application duration time, there is a check box option on the left side of the VTune window which allow multiple runs.

You can select the duration from the drop down above the check box.

If this resolves your issue, make sure to accept this as a solution. This would help others with similar issue. Thank you!

Regards,

Remya Premdas

[Srihari_S]

Hi. Thanks for the reply. I tried the option. But in your reply I saw it was for application. So will this help in timing of individual functions being consistent. When I ran with the option you told, it seemed to run only one run(Opened the terminal and executed once). Your thoughts on this?

[RemyaP_Intel]

Hi,

Yes. Though you select 'allow multiple run', you will see the terminal opening once and a single report will be generated. Ideally the timing of individual functions should also be consistent. 

The number of events VTune can monitor during a single run is limited by the number of performance counters in your processor. If you enable multiple runs of the data collection, the VTune Profiler runs the hardware event-based sampling data collector as many times as required to collect data on all the events specified for the analysis type.

If you specified an application to launch as an analysis target, the VTune Profiler launches your application each time the hardware event-based sampling collector runs.

Please have a look at this document : https://www.intel.com/content/www/us/en/docs/vtune-profiler/user-guide/2023-0/allow-multiple-runs-or-multiplex-events.html

Regards,

Remya Premdas

[RemyaP_Intel]

Hi,

We haven't received any response from your end. Is your issue resolved?

Regards,

Remya Premdas

[RemyaP_Intel]

Hi,

We assume that your issue is resolved. If you need any additional information, please post a new question as this thread will no longer be monitored by Intel

Regards,

Remya Premdas