To perform What If? analysis, you can set toggle rates and static probability on nets and cells in the design. To make these settings, right-click any net or cell from the Netlist window or Power Report and click Properties, and go to the Power view in the Properties window as shown in the following figure. Then click the Load Properties button in the Power view. Click Edit Properties and set the Toggle Rate and Static Probability in the Edit Power Properties dialog box that appears, and click OK.
In the example above the Toggle Rate has been set to 1.5% and Static Probability is set to 0.8. On the Tcl Console the following XDC constraint will be displayed when the Vivado Integrated Design Environment commits the change on OK.
set_switching_activity -toggle_rate 1.500000 -static_probability 0.800000 [get_nets led]