TMC-20002: Timing Paths with Removal Slack Exceeding Threshold
Description
Violations of this rule identify timing paths with removal slack below the slack threshold parameter. Timing paths with a very large negative removal requirement complicate timing closure and may cause excessive run times. Such paths are likely invalid, 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