To examine the impact of the
Performance_Explore
strategy on meeting timing, change the
timing constraints to make timing closure more challenging. - In the Sources window, double-click the top_full.xdc file in the
constrs_2
constraint set.The constraints file opens in the Vivado IDE text editor.
- On line 2, change the period of the
create_clock
constraint from10 ns
to7.35 ns
.The new constraint should read as follows:
create_clock -period 7.35 -name sysClk [get_ports sysClk]
- Save the changes by clicking the Save File
button in the toolbar of the text editor.
Note: Saving the constraints file changes the status of all runs using that constraints file from “Complete” to “Out-of-date,” as seen in the Design Runs window.
- In the Design Runs window, select all runs and click the Reset Runs
button.
- In the Reset Runs dialog box, click Reset.
This directs the Vivado Design Suite to remove all files associated with the selected runs from the project directory. The status of all runs changes from “Out-of-date” to “Not started.”
- With all runs selected in the Design Runs window, click the Launch Runs
button.
The Launch Selected Runs window opens.
Tip: You can also launch runs without resetting them first. If the runs are out of date, the Reset Runs dialog box displays. In this dialog box, you can reset the runs before they are launched. - Select Launch runs on local host and
Number of jobs: 2 and click OK.
When the active run (
impl_3
) completes, the Implementation Completed dialog box opens. - Click Cancel to close the dialog box.
- Compare the Elapsed time for each run in the Design Runs window, as seen in
the following figure.
- The
impl_2
run, using thePerformance_Explore
strategy is closest to meeting timing, but also took the maximum amount of time to complete.
Note: Reserve thePerformance_Explore
strategy for designs that have challenging timing constraints and fail to meet timing with the Implementation Defaults strategy. - The