A quality-of-service mechanism for interconnection networks in system-on-chips

As Moore´s Law continues to fuel the ability to build ever increasing complex systems-on-chips (SoCs), achieving performance goals is rising as a critical challenge to completing designs. In particular, the system interconnect must efficiently service a diverse set of data flows with widely ranging quality-of-service (QoS) requirements. However the known solutions for off-chip interconnects, such as large-scale networks, are not necessarily applicable to the on-chip environment. Latency and memory constraints for on-chip interconnects are quite different from larger-scale interconnects. The paper introduces a novel on-chip interconnect arbitration scheme. We show how this scheme can be distributed across a chip for high-speed implementation. We compare the performance of the arbitration scheme with other known interconnect arbitration schemes. Existing schemes typically focus heavily on either low latency of service for some initiators or on guaranteed bandwidth delivery for other initiators. Our scheme allows service latency on some initiators to be traded off smoothly against jitter bounds on other initiators, while still delivering bandwidth guarantees. This scheme is a subset of the QoS controls that are available in the SonicsMX™ (SMX) product.