Intel® Arria® 10 Hard Processor System Technical Reference Manual

ID 683711
Date 1/10/2023
Public

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8.2.11. Functional Description of the QoS Generators

Quality of service is managed by information generated by a QoS generator at each initiator interface (master). The QoS generators work with the arbitration logic so you can tune the interconnect's performance to your system needs.

At the entry points to the system interconnect, the QoS generators create the following information to control how the arbitration logic allocates interconnect bandwidth among all transactions:

  • Urgency—Each master has an urgency value. When it initiates a packet, it assigns a priority equal to its urgency.
  • Pressure—Each data path has a pressure value. If the pressure is raised, packets on that path are treated as if their priority was also raised.
  • Hurry—Each master has a hurry value. If the hurry is raised, all packets from that master are treated as if their priority was also raised.

The QoS information is used at each interconnect arbitration node to assign a packet priority. When there is contention for a resource, the arbitration logic generally gives the resource to the packets with higher priority.

For detailed descriptions of urgency, pressure, and hurry, refer to "QoS Mechanisms".

The values of urgency, pressure, and hurry are determined by each QoS generator's operating mode. QoS generators support the following modes:

  • Limiter
  • Regulator
  • Fixed

For detailed descriptions of the QoS generator modes, refer to "QoS Generator Modes".