Introduction
End-to-end quality of service (QoS), included in the Arteris FlexNoC, FlexGen and FlexWay interconnect IP, helps ensure that all on-chip data flows can meet their latency and bandwidth requirements, while sharing limited memory subsystem bandwidth. As modern SoCs integrate numerous heterogeneous IP blocks, QoS becomes essential for delivering predictable, real-time performance across the entire transport network.
What is end-to-end QoS?
End-to-end QoS provides coordinated control of latency, bandwidth, arbitration, traffic prioritization, and flow management across the full on-chip network—from initiator to target. Its purpose is to ensure each traffic type receives the required service level needed to maintain system performance, especially under varying workload conditions.
Heterogeneous traffic types in SoCs
Each IP block in an SoC generates traffic with its own characteristics, including protocol type, frequency, data width, throughput requirements and tolerance to latency. Arteris FlexNoC, FlexGen and FlexWay QoS is designed to manage these diverse, and sometimes conflicting, performance needs.| Initiator | Traffic Profile | Reason |
|---|---|---|
| CPU | Latency sensitive | Processing stops for many cycles when there is a cache miss. |
| Video Display | Real time & latency critical | The video display subsystem’s buffer must never be empty or the end-user will see black pixels. |
| Imaging System | Real time & bandwidth sensitive | Works several frames ahead and adjusts quality dynamically. |
| Background File Download | Best effort | Pauses do not affect the user experience. |
Dynamic arbitration and packet prioritization
The Arteris network-on-chip (NoC) assigns packet-level priorities to help ensure traffic reaches its destination within required service windows. Priorities can be applied per packet or per socket, and can be adjusted dynamically at runtime to reflect changing system needs.
FlexGen, FlexNoC and FlexWay also provides dynamic pressure propagation, which detects when high-priority packets may be blocked by downstream congestion and proactively clears a path. This behavior is similar to how traffic yields for an emergency vehicle, ensuring critical packets move quickly and predictably through the network.
Bandwidth limiters and rate regulators
When QoS information is not provided directly by IP blocks, FlexGen, FlexNoC and FlexWay can generate it using the QoS Generator. This provides software-programmable mechanisms to regulate traffic rates and enforce bandwidth guarantees throughout the NoC.
Bandwidth limiters
Bandwidth limiters prevent a socket from accepting new requests once a programmable throughput threshold is exceeded. This helps protect downstream resources and stabilizes QoS behavior.
Rate regulators
Rate regulators demote socket transactions when bandwidth usage exceeds configured levels. Unlike a hard stall, rate regulation smooths traffic without halting initiators entirely.
In summary
End-to-end QoS is essential for predictable and high-performance SoC operation. Arteris FlexGen, FlexNoC and FlexWay delivers dynamic priorities, congestion awareness, bandwidth regulation and runtime configurability to ensure that every traffic type receives the appropriate service level across complex, heterogeneous systems.
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Arteris FlexGen Interconnect IP
