Optimistic, eager rendezvous transmission system and combined rendezvous system for message processing, and related data structures

摘要

A method, system, and associated program code and data structures are provided for a message processing system in which messages are transmitted from source nodes to destination nodes. An "eager" rendezvous transmission mode is disclosed in which early arrival buffering is provided at message destination nodes for a predetermined amount of data for each of a predetermined number of incoming messages. Relying on the presence of the early arrival buffering at a message destination node, a message source node can send a corresponding amount of message data to the destination node along with control information in an initial transmission. Any remaining message data is sent only upon receipt by the source node of an acknowledgement from the destination node indicating that the destination node is prepared to receive any remaining data. In an enhanced embodiment, the source node alternates between rendezvous transmission modes as a function of the amount of free space in the early arrival buffering at the destination node, as indicated by the number of outstanding initial transmissions for which acknowledgements have not yet been received. Different transmission modes for different destination nodes can be employed at a source node, depending on the amount of early arrival buffering currently available in each respective destination node.