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Vtune Metrics discrepancy (uOps vs Instructions)

Donghyeon
Beginner
487 Views

Hello. 

I am currently in academics and profiling Transformer performance on VTune. 

 

The metrics used on the results of microarchitecture exploration are mostly "% of pipeline slots" entering the front end and exiting the back end, thus relative to the number of uOps, or microcode. 

And yet the foremost two results are  "Instructions retired" and "CPI Rate", based on the number of 'instructions' which I understood as instruction BEFORE being decoded into uOps.  

 

I'm having a hard time understanding why the metrics aren't unified into either using uOps-only or Instructions-only. I think the logical choice would be using uOps-based metric as computing resources operate on uOp-level. Then shouldn't "Cycle per uOp" and "uOps retired" be a more readily used metric? 

 

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4 Replies
JyothisV_Intel
Moderator
462 Views

Hi,


Good day to you.


Thanks for posting in Intel Communities.


We are working on this internally and will get back to you with an update.


Regards,

Jyothis V James


Dmitry_R_Intel1
Employee
403 Views

In general I would agree - metrics in uops better characterize any particular microarchitecture. But uops are very microarchitecture-specific. So metrics in retiring instructions still make sense and quite useful when you want to compare cross-microarchitecture or even cross-architecture. E.g. if you compare Intel Icelake with Intel Haswell or some Intel CPU with AMD CPU or ARM CPU.

JyothisV_Intel
Moderator
368 Views

Hi,

 

Good day to you.

 

We have not heard back from you. We hope that you got some clarity regarding the query which you raised.

 

If yes, do let us know so that we can stop monitoring this thread.

If not, kindly get back to us with your valuable suggestions and queries since, we are always open to community feedback regarding our products and services.

 

Thanks and Regards,

Jyothis V James

 

JyothisV_Intel
Moderator
320 Views

Hi,

 

Good day to you.

 

We assume that your doubts are cleared since we have not heard back from you.

 

If you need any additional information, please post a new question as this thread will no longer be monitored by Intel.

 

Thanks and Regards,

Jyothis V James

 

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