During design implementation, the placer determines the locations of the NMU / NSU / DDRMC endpoints. Unless explicitly located by a user constraint, the locations are assigned as a result of the placer’s efforts to obtain a solution that is optimized for the fabric to close timing. The traffic specification is not taken into account. When assigned, the placer calls the NoC compiler with the endpoints assigned to route the NoC nets and satisfy the traffic specification.
The Vivado placer setting -no_noc_opt runs the NoC compiler in preplace mode. In this mode, the
placement of fabric is driven by the placement of NoC instances. This results in better
NoC QoS. However, using this option can make it more difficult to close timing.