METHOD AND SYSTEM FOR FLEXIBLE CREDIT EXCHANGE WITHIN HIGH PERFORMANCE FABRICS

摘要

Method, apparatus, and systems for implementing flexible credit exchange within high performance fabrics. Available buffer space in a receive buffer on a receive-side of a link is managed and tracked at the transmit-side of the link using credits. Peer link interfaces coupled via a link are provided with receive buffer configuration information that specifies how the receive buffer space in each peer is partitioned and space allocated for each buffer, including a plurality of virtual lane (VL) buffers. Credits are used for tracking buffer space consumption and in credits are returned from the receive-side indicating freed buffer space. The peer link interfaces exchange credit organization information to inform the other peer of how much space each credit represents. In connection with data transfer over the link, the transmit-side de-allocates credits based on an amount of buffer space to be consumed in applicable buffers in the receive buffer. Upon space being freed in the receive buffer, the receive-side returns credit ACKnowledgements (ACKs) identifying a VL for which space has been freed.

主权项

1. An apparatus, comprising:
a link interface including,
a receive port; anda transmit port;wherein the receive port and transmit port comprise circuitry and logic to,
receive data defining an initial receive buffer configuration of a receive port of a peer link interface of a peer apparatus to which the apparatus is configured to be linked in communication, the receive buffer configuration comprising an overall buffer space partitioned into a plurality of buffers including a plurality of virtual lane (VL) buffers, each allocated for a respective VL, the data including an initial allocation of credits for each buffer;receive credit organization information conveying an amount of buffer space represented by each credit;transmit data outbound onto the link to be received by the receive port of the peer link interface;de-allocate buffer credits at the transmit port for applicable buffers in the receive buffer based on an amount of transmitted data and the credit organization information;receive credit return ACKnowledgements (ACKs) from the peer link interface, each credit return ACK identifying a VL and one or more credits conveying an amount of freed buffer space for a buffer allocated for the VL and based on the credit organization information; andtrack, at the transmit port, available credits for each buffer in the receive buffer based on the de-allocated buffer credits and credits returned via the credit return ACKs.