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AR# 66091

2015.4 XPE/Report Power - Power Model Updates for UltraScale Devices in 2015.4

Description

What have been changed in 2015.4 XPE and Report Power for UltraScale and UltraScale+ devices?

Solution

The power model and related user entry criteria have been changed for UltraScale and UltraScale+ devices in 2015.4 XPE and Vivado Report Power. 

These changes were made in an effort to improve the overall accuracy of the tools.

The following three models were updated:

  • Logic & Signal modeling
  • DSP modeling
  • BRAM modeling

Logic & Signal Modeling:

Increase in analysis accuracy is based on physical routing characteristics of the design, which impacts the dynamic power. 

The "Routing Complexity" field replaces the "Logical Fanout" field. See (Xilinx Answer 66038) for more details.

You will see an increase in the estimated power by ~1-2%, but results depend on the specific situation.

DSP Modeling:

Increase in analysis accuracy is based upon input toggle rate rather than output toggle-rates. 

You will need to change the toggle-rates to reflect the inputs, instead of the outputs. The input toggle-rates are usually lower than the output toggle-rates.

You will see a small reduction in estimated power, but results depend on the specific situation.

BRAM Modeling:

Increase in analysis accuracy is based on improvements of the modeling to reflect low enable-rate situations and clock power contributions. 

The toggle-rates now reflect an average of input and output toggle-rates. You need to change the toggle-rates to reflect an average of input and output toggle-rates.

You will see an increase in estimated power by 1-2%, but results depend on the specific situation.


For customers needing more details about these changes a PDF has been created to provide detailed information about the changes and how they impact the design estimation compared to prior versions.

The PDF is attached to this answer record. If you still have questions, please contact your FAE or open a Service Request.

Attachments

Associated Attachments

Name File Size File Type
Power_Estimation_2015_4_Update.pdf 202 KB PDF
AR# 66091
Date Created 12/03/2015
Last Updated 12/04/2015
Status Active
Type General Article
Devices
  • Kintex UltraScale
  • Virtex UltraScale
Tools
  • Vivado Design Suite