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AlexanderPanov
Beginner
92 Views

UPI frequency

Hello,

Could anybody show me,  where I can make sure how to convert a transfer rate to the clock rate for UPI? Or where to see exactly numbers from Intel docs.

For example, for QPI, the Wiki says:
"Intel describes the data throughput (in GB/s) by counting only the 64-bit data payload in each 80-bit flit. However, Intel then doubles the result because the unidirectional send and receive link pair can be simultaneously active. Thus, Intel describes a 20-lane QPI link pair (send and receive) with a 3.2 GHz clock as having a data rate of 25.6 GB/s. A clock rate of 2.4 GHz yields a data rate of 19.2 GB/s. More generally, by this definition a two-link 20-lane QPI transfers eight bytes per clock cycle, four in each direction.

The rate is computed as follows:

3.2 GHz
× 2 bits/Hz (double data rate)
× 16(20) (data bits/QPI link width)
× 2 (unidirectional send and receive operating simultaneously)
÷ 8 (bits/byte)
= 25.6 GB/s"

For UPI transfer rate is 10.4 GT/s.
How to get the corresponding physical frequency in one separate diff. pair?
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3 Replies
AlexanderPanov
Beginner
87 Views

Need to clarified:

The Wiki says about bit rate (GB/s), but for UPI specified the transfer rate (GT/s).


Is this means that we only need to take into account:
unidirectional send and receive operating simultaneously,
the doubling because of reading in fall and rise of clock signal (if it is present)
?

Victor_G_Intel
Moderator
63 Views

Hello AlexanderPanov,


Thank you for posting on the Intel® communities.


We appreciate the information provided and we will use it to do further research about your request and, we will update this thread as soon as possible.


I look forward to hearing from you.


Regards,


Victor G.

Intel Technical Support Technician  


IntelSupport
Community Manager
41 Views

Hello AlexanderPanov,


We are updating this thread to let you know that we are still looking into your request. 


We also found another ticket describing a similar concern. We will provide further updates through this support ticket so that we can contact you directly, and assist you as soon as possible.


Regards,


Wanner G.

Intel Customer Support Technician