Advanced Quality of Service (QoS-301, QoS-400) is an option for the Features of the CoreLink Advanced Quality of Service
QoS manages data traffic at entry to the network interconnect using targeted hardware resource for critical components. QoS, in combination with the CoreLink Dynamic Memory Controllers (DMC-400, DMC-34x):
- Minimizes average latency for best-effort masters,
- Whilst guaranteeing bandwidth & latency for real-time traffic.
QoS dynamically adjusts a master's priority to meet its target transaction latency. Masters operate at the lowest priority they need, freeing system resources for use by others. Traffic shaping manages the system queues and guarantees the memory controller queue does not block other paths in the interconnect.
QoS is fully integrated with AMBA Designer, allowing the SoC designer to configure the QoS hardware alongside the CoreLink Network Interconnect (NIC-400, NIC-301).
QoS Virtual Networks prevent blocking
QoS Virtual Networks (QVN-400) use a priority driven allocation of buffer space in both the interconnect (NIC-400) and the memory controller (DMC-400) to provide virtual channels over the same set of resources to prevent cross-stream and head-of-line blocking. This ensures that there is always a clear path for higher priority traffic types such as timeout critical transfers and latency sensitive CPU loads, while at the same time making the maximum amount of bandwidth available to latency-tolerant masters such as media processors.
