Mechanisms for arbitrating among packets in hierarchical arbitration architecture

Abstract

In an embodiment, a computer system comprises one or more co-packaged integrated circuits having a communication fabric that couples various agent circuits. The agent circuits transmit packets via the communication fabric, which can include command-data packets and command packets. In various embodiments, the communication fabric includes an arbitration circuit to arbitrate among packets to transmit on the fabric. The command-data packets may be allocated to a first plurality of virtual channels while the command packets are allocated to a second plurality of virtual channels. The arbitration circuit may arbitrate among the first plurality of virtual channels to select a command-data packet and the second plurality of virtual channels to select a command packet. The arbitration circuit may then arbitrate between the selected command-data packet and the selected command packet to select a winning packet to transmit based on a history of previously selected packets.