Often designs have multiple paths sharing the NoC, but without all paths needing maximum bandwidth simultaneously. Rather, some paths can be active during one phase of activity, while others are idle. During another phase, the original paths can require less bandwidth, while the paths that had been idle can require more bandwidth. If the design assumes that all paths require their maximum possible bandwidth at all times, the NoC compiler might not find a solution that satisfies all the bandwidth requirements simultaneously. In these cases, it can be beneficial to define different traffic phases.
To enable Multiphase NoC Mode, after creating the project, define the different phases
with set_property NOC_PHASES. For example, the following command
defines three traffic phases.
set_property NOC_PHASES “boot_phase, config_phase, end_phase” [current_project]This command only needs to be run one time and is applied to all NoC IP
instances in the design. It adds a new Multiphase
Mode column to the QoS tab. By checking the Multiphase
Mode check box next to a path, you can specify read and write bandwidth
on a per-phase basis. In this example, the path from S00_AXI to M00_AXI has different
bandwidths specified for boot_phase, config_phase, and end_phase. Paths without multiphase checked are assumed to have the same
bandwidth for all phases.