Every connection through the NoC has an associated quality of service (QoS) requirement. The set of desired NoC connections together with their corresponding QoS requirements constitute a traffic specification. The NoC compiler uses the traffic specification internally to compute a configuration for the NoC.
A QoS requirement includes the following two components:
- Traffic class
- Defines how the NoC compiler and hardware prioritizes traffic on the connection. The traffic class is set at the NMU and is for all paths starting from that NMU.
- Read and write bandwidth requirements
- Describes how much data bandwidth the connection is expected to consume in each direction. Bandwidth requirements are associated with the egress port (NoC slave). Each connection can have different read and write bandwidth requirements. Bandwidth can be in units of MB/s or Gb/s.
The final performance of the NoC is subject to the accuracy of the QoS information provided. The NoC does not rate-limit traffic based on the QoS specification. A master port that exceeds the provided QoS specification negatively impacts the performance of the other Best Effort connections it shares resources with.