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KAnna2
Beginner
321 Views

Where to find IPC (or cpi) value of Intel processors (say skylake) when diff no of physical and logical cores are used?

I am very new to this field and my question might be too stupid but please help me understand the fundamental here.

 

I want to know the instruction per cycle (ipc) or clock per instruction (cpi) of recent intel processors such as skylake or cascade lake. And I am also looking for these values when different no of physical cores are used and when hyper threading is used.

 

I thought spec cpu2017 benchmark results could help me here, but I could not find my ans there. They just compare the total execution time by time taken by some reference machine and gives the ratio. Am I missing something here?

 

I thought this is one of the very first performance parameters and should be calculated and published by some standard benchmark, but

I could not find any. Am I missing something here?

Another related question which comes to my mind (and I think everybody might want to know) is what is the best it can provide using all the cores and threads (least cpi and max ipc)?

Please help me find ipc / cpi value of skylake (any Intel processor) when say maximum (28) cores are used and when hyperthreading is also enabled.​

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2 Replies
n_scott_pearson
Super User Retired Employee
233 Views

The problem is that Intel processors are CISC machines. The CPI varies from one instruction to another. What mix of instructions you want the question answered for can make a huge difference. With features like Turbo Boost, etc., the frequency of a core can be different based upon all sorts of factors. Then there's the differences in cache sizes and differing efficiencies based upon differing bus and memory clock speeds. Bottom line, there are simply too many factors to take into account; answering your IPC/CPI question on Skylake is next to impossible to do.

 

No one has ever been able to agree on a standard benchmark. Intel and AMD both are going to use whatever benchmark advantages the processors that they are currently trying to highlight.

 

Sorry, no help here,

...S

AdrianM_Intel
Moderator
233 Views

Hello KAnna2,

 

Thank you for submitting your question on this Intel® Community. 

 

Regarding this question, you might try Intel Resource & Design Center for further assistance.

 

Regards,

 

Adrian M.

Intel Customer Support Technician

 

 

 

 

 

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