Hamlyn: a high-performance network interface with sender-based memory management

• automatic message reassembly even if packets arrive out of order, which allows use of adaptive-routing networks having greater throughput and fault-tolerance; • simple design: the interface can be implemented directly in hardware state machines for speed; • protection against node failures and rogue messages: eliminates need for per-message software checks; • a rich set of message-delivery notification schemes gives applications choices between minimizing latency and maximizing functionality. The first Hamlyn design incorporated most of these features [Wilkes92]. It was developed as a way to integrate a fast, packet-switched interconnect, known as FedEx, 1 which supported adaptive routing into a large-scale MIMD multicomputer. This work expands on that design by: • reporting performance data from software and hardware prototypes; • extending the schemes available for notification of message arrival; • extending the original packet-counting scheme to a more powerful one that supports generalized group-receive semantics; • presenting low-level protocols that sit atop the hardware interface. Hamlyn was designed with a RISC-like philosophy: make the common cases fast, and the less common ones 1. FedEx was the successor to the PostOffice switching chip developed by the HP Labs Mayfly project [Davis92].