International Business Machines Corporation

Robert Michael Straub

Rama Krishna Govindaraju

Hubertus Franke

Pratap Chandra Pattnaik

Mandayam Thondanur Raghunath

William G Tuel, Jr

Elizabeth Anne Kon

Ronald G Coleman

Deepak Mohan Advani

Yun-Pong Huang

Owen K Monroe

Miner H Gleason, Iii

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 &ldquo;eager&rdquo; 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.

Optimistic, eager rendezvous transmission mode and combined rendezvous modes for message processing systems

Hybrid lock and unlock capabilities are provided for a threaded computing environment. For example, kernel locking services are selectively employed in conjunction with functions in the POSIX threads standard to provide a lock capability and an unlock capability. The hybrid approach determines which lock scheme to employ by evaluating whether one thread or multiple threads concurrently desire a resource lock. When only one thread desires the lock, the thread is directly assigned resource ownership employing one of an operating system primitive lock process or a hardware lock process. An alternate lock process is used to obtain resource ownership when multiple threads concurrently desire the lock. This alternate process employs at least one function in the POSIX threads standard to implement a queue of waiting threads. A similar hybrid approach to the unlock capability is also provided.

Method for resource lock/unlock capability in multithreaded computer

Resource lock/unlock capability in multithreaded computer environment

System for resource lock/unlock capability in multithreaded computer

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.

Optimistic, eager rendezvous transmission system and combined rendezvous

Apparatus and an accompanying method for implementing a communications protocol for use in generally a distributed, and particularly a highly parallel, multi-processing system (5), for communicating application data of arbitrarily varying strides between separate processors and generally without the need for intermediate data storage. Specifically, application data is transferred through a succession of packets (770) between originating and destination application programs (252), with each packet containing a partial data message. Each partial data message contains a portion of the data that is stored in a stride one portion of an originating application data memory (700). Upon reception, each data portion is written into a stride one portion of a destination application data memory (760). An application interface (254), executing independently at both the originating and destination processing elements (10.sub.1, 10.sub.J+1) locally and respectively determines the starting address and length of each separate stride one data portion stored in the originating application data memory and for each separate stride one area in the destination application program memory that is to receive application data.

Communication protocol for handling arbitrarily varying data strides in

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Poughkeepsie, NY, United States of America

Robert Michael Straub