You can use the group_path command with
the -weight 2 option to give higher priority to the
path endpoints defined in a clock group. For example, to assign a higher priority to
group of logic clocked by a specific clock, use the following command:
group_path -name [get_clocks clock] -weight 2clock with a weight of
2 over other paths in the design.High priority path groups are treated with the highest priority in
the placer and router during timing optimization. During phys_opt_design, high priority path groups are prioritized during the
Critical Path Optimization phase.
When using the -weight option,
consider the following:
- Carefully choose which path groups to apply high priority to,
because this approach might degrade other clocks that are near critical.Note: It is easier to control the impact of the high priority path group when applied to smaller clock domains. AMD recommends reserving high priority for high frequency clocks.
- This option is not
recommended for use on:
- Highly-congested designs because timing optimization can further degrade congestion
- Clocks driving modules with high netlist complexity, with high Rent exponent (above 0.65)
- Clocks that have high hold timing violations
For more information on the group_path
command, see group_path in the
Vivado
Design Suite Tcl Command Reference Guide (UG835).