An Implementation of the Hamlyn Sender-Managed Interface Architecture

As the latency and bandwidth of multicomputer interconnection fabrics improve, there is a growing need for an interface between them and host processors that does not hide these gains behind software overhead. The Hamlyn interface architecture does this. It uses sender-based memory management to eliminate receiver buffer overruns, provides applications with direct hardware access to minimize latency, supports adaptive routing networks to allow higher throughput, and offers full protection between applications so that it can be used in a general-purpose computing environment. To test these claims we built a prototype Hamlyn interface for a Myrinet network connected to a standard HP workstation and report here on its design and performance. Our interface delivers an application-to- application round trip time of 28us for short messages and a one way time of 17.4us + 32.6ns/byte (30.7MB/s) for longer ones, while requiring fewer cpu cycles than an aggressive implementation of Active Messages on the CM-5.