Using Directives - 2021.1 English

When routing the entire design, directives provide different modes of behavior for the route_design command. Only one directive can be specified at a time. The directive option is incompatible with most other options to prevent conflicting optimizations. The following directives are available:

Explore

Allows the router to explore different critical path placements after an initial route.

AggressiveExplore

Directs the router to further expand its exploration of critical path routes while maintaining original timing budgets. The router runtime might be significantly higher compared to the Explore directive because the router uses more aggressive optimization thresholds to attempt to meet timing constraints.

NoTimingRelaxation

Prevents the router from relaxing timing to complete routing. If the router has difficulty meeting timing, it runs longer to try to meet the original timing constraints.

MoreGlobalIterations

Uses detailed timing analysis throughout all stages instead of just the final stages, and runs more global iterations even when timing improves only slightly.

HigherDelayCost

Adjusts the internal cost functions of the router to emphasize delay over iterations, allowing a tradeoff of run time for better performance.

RuntimeOptimized

Run fewest iterations, trade higher design performance for faster run time.

AlternateCLBRouting

Chooses alternate routing algorithms that require extra runtime but may help resolve routing congestion.

Quick

Absolute, fastest compile time, non-timing-driven, performs the minimum required for a legal design.

Default

Run route_design with default settings.