Systems and methods for accurate link loop latency measurement and dynamic backlog reduction of receiver buffer

A system comprising:

• a plurality of nodes, each node connected to an interconnect fabric for transmission of datagrams between link partners, each node comprising:
• at least one processor coupled to a data fabric;
• at least one storage media coupled to the data fabric;
• and
• at least one circuit coupled between the data fabric and an interconnect link of the interconnect fabric for transmission of data between the data fabric and the interconnect link, the at least one circuit comprising:
• a receiver configured to convert datagrams received from a link partner over the interconnect fabric into electrical signals to send to a storage media over the data fabric, and
• a transmitter configured to convert a data stream from electrical signals received from the data fabric into datagrams for transmission to the link partner over the interconnect fabric,
• wherein the transmitter is further configured to monitor a loop latency for datagrams communicated with the link partner over the interconnect fabric using toggling handshake codes in a header of the datagrams, and
• wherein, based on the monitored loop latency for the datagrams, the transmitter is configured to reduce a receiver buffer backlog at the link partner.

A method comprising:

• measuring a first loop latency for data transmissions of datagrams between two link partners over at least one interconnect link, a header of the datagrams including one of a first value and a second value;
• measuring a second loop latency for data transmission of datagrams between the two link partners over the at least one interconnect link;
• calculating, by a link partner, a value characterizing a degree of a backlog in a receiver buffer of the other link partner based on the measured first loop latency and the measured second loop latency;
• and
• responsive to the calculated value exceeding at least one threshold, transmitting, by the link partner, at least one non-operative (NOP) datagram to the other link partner over the at least one interconnect link, the at least one NOP datagram configured to reduce the backlog in the receiver buffer of the other link partner.