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Brian__Vikkor
Beginner
108 Views

Out of bounds roofline results

For some reason points on the roofline model corresponding to my loops are out of bounds of the roofline model

How it is possible? How to interpret this result? Microarchitecture analysis of vtune amplifier shows a lot of space for optimization.

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2 Replies
Dmitry_Dontsov
Employee
108 Views

Hi,

Could You please provide project directory?

Zakhar_M_Intel1
Employee
108 Views

Hello!

 

What is a total duration of your test case? Does it run (without advisor) for 1 or 2 seconds, for several minutes or for several hours?

 

The vertical coordinate of dots is FLOP/Seconds. If seconds --> 0 , then FLOP/Seconds --> infinite. The only case when seconds --> 0 is when the time spent in those kernels is smaller or same as "sampling interval" (10-50 milliseconds). In cases like that hotspots statistical sampling will not properly capture the time spent in the kernels and therefore FLOP/S will be "exaggerated".

You have to run your code for at least 10 or 20 seconds to make the case statistically representative and have correct FLOP/S data.

 

 

 

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