1.Observe the negative setup/hold slack with the default tap value from the timing report.
2.Increase or decrease one tap value and observe the delay improvement related to IDELAYE5 or ODELAYE5 primitives from the timing report.
3.Based on single tap value delay improvement and with the negative setup/hold slack reported, calculate the proper tap value.
4.If not possible to meet the timing with the tap value then need to update the input/output delay constraints in the XDC for the related ports to meet the timing.