HRR-10115: High Fan-out Signal
Description
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
Device Family
- Intel® Stratix® 10
- Intel® Agilex™