The following table provides a guideline for the recommended number of control sets, depending on the target device size.
Guideline | Percentage of Control Sets |
---|---|
Acceptable | Less than 7.5% of the total number of control sets in the device |
Reduction Recommended | Between 7.5% and 15% of the total number of control sets in the device |
Reduction Required | Greater than 15% of the total number of control sets in the device |
These guidelines assume the following:
- Typical control set capacity: 1 per 8 CLB registers
- Total number of control sets in a device: CLB registers / 8
Determine the number of control sets in a design
using report_control_sets -verbose
.
Tip: Too
many control sets can cause localized congestion and force route detours.
Identifying the high local density of unique control sets requires detailed
placement analysis in the Vivado IDE
Device window, which
includes highlighted control signals in different colors.