HRR-10115: High Fan-out Signal

High fan-outs nets limit the performance of designs using Intel® Hyperflex™ architecture. High fan-out may contain long or short path imbalances that limits retiming in critical chains.

Parameter

Name Default Value Description
Fanout 500

Reports a violation for drivers that have at least the number of fan-outs specified in this parameter.
Driver_Name_Filter  

Reports a violation for high fan-out drivers that do not match any of the name patterns specified in this parameter. The list of patterns is space-separated. Patterns can contain wildcard characters ('*' and '?') and hierarchy separator ('|'). Wildcards do not match any hierarchy separator in a hierarchical name. To support natural specification of bus-bit indices, square brackets '[', ']' in a pattern are treated as plain characters (they do not denote a set of characters).

Recommendation

Duplicate high fan-out driver registers. Refer to DUPLICATE_REGISTER and DUPLICATE_HIERARCHY_DEPTH assignments for automated solutions. Alternatively, you can edit the RTL to create duplicate copies.

If you edit the RTL, apply the preserve_syn_only attribute to duplicate registers and assign the duplicates to individual instances in the fan-out hierarchy.

Severity

Low

Stage

Analysis and Elaboration

, Plan

Device Family

  • Intel® Stratix® 10
  • Intel® Agilex™
  • Intel® Cyclone® 10 GX
  • Intel® Arria® 10