Automatic Incremental Implementation Mode - 2020.2 English

UltraFast Design Methodology Guide for Xilinx FPGAs and SoCs
Document ID
UG949
Release Date
2021-02-18
Version
2020.2 English

You can use automatic incremental implementation mode to activate the incremental implementation flow but allow the Vivado tools to defer running incremental implementation until more is known about the reference checkpoint and the current design. When the read_checkpoint command is issued, the Vivado tools determine whether to run the implementation flow with the default flow algorithms or with the incremental flow algorithms. Automatic mode provides push-button ease of use, because the tools manage the reference design data for incremental implementation.

Note: The automatic incremental implementation mode is less aggressive than running the default incremental implementation flow and enables better maintenance of QoR when running the incremental implementation flow.

Project Mode

In Project Mode, the Vivado tools manage updating of the checkpoint as well as which algorithms to use. To enable the automatic incremental implementation mode in Project Mode, right-click an implementation run in the Design Runs window, select Set incremental Compile > Automatically use the checkpoint from the previous run.

The equivalent Tcl command is:
set_property AUTO_INCREMENTAL_CHECKPOINT 1 [get_runs <runName>]

Non-Project Mode

In Non-Project Mode, the Vivado tools manage which algorithms to use, but you must decide whether to update the checkpoint. To enable the automatic incremental implementation mode in Non-Project Mode, use the -auto_incremental option. Following is an example command:
read_checkpoint -incremental -auto_incremental <reference>.dcp
When updating the checkpoint, ensure that WNS did not degrade beyond acceptable limits by using the following command at the end of the implementation flow:
if {[get_property SLACK [get_timing_path -setup]] > -0.250} {
	file copy -force <postroute>.dcp <reference>.dcp
}