TMC-20004: Timing Paths with Setup Slack Exceeding Threshold
Description
Violations of this rule indicate timing paths with setup slack below the slack threshold parameter. Timing paths with very large negative slack complicate timing closure and can cause excessive run time. Such paths are likely not valid, and require appropriate timing constraints.
Parameters
| Name | Description | Type | Default Value | Min Value | Max Value |
|---|---|---|---|---|---|
| slack_threshold | A violation is reported for timing paths that have slack more negative than the value of this parameter. | double | -5.0 | 0.0 |
Recommendation
Ensure that each timing path is valid, and apply SDC constraints to cut the path or adjust its slack. For example:
- set_clock_groups constraint can avoid invalid clock domain crossing paths.
- set_false_path constraint marks invalid timing paths.
- set_multicycle_path constraint adjusts clock edges of a multi-cycle path.
Severity
Medium
Tags
| Tag | Description |
|---|---|
| impossible-requirements | Design rule checks which check the requirements on failing timing paths and flag those which fail by construction. |
| sdc | Design rule checks related to SDC validity checking. |
Device Family
- Intel®Agilex™
- Intel®Stratix® 10
- Intel®Arria® 10
- Intel®Cyclone® 10 GX