International Business Machines Corporation

Scott Andrew Fagen

Jeffrey Mark Nick

Richard Charles Williams

Jeffrey Alan Frey

Christopher Paul Vignola

Carroll Eugene Fulkerson, Jr

Jon Kim Johnson

John T Gates, Jr

John P Kong

Ramu Mohan

Benjamin John North

Mark Albert Kowalski

Lorraine Cramer

A message processing facility provides a send function for sending messages to designated locations. The facility allows a default target for a message, initiates parallel execution, adds additional processes to an already parallel execution, determines that a problem has completed and performs the appropriate completion actions. The message processing facility enables coordination of the results of a network that has been widened in its parallelism, without creating subproblems. Processes within the parallel network do not need to be aware of the topology or the position of a given process within the topology. The width of the parallelism involved in a particular request is tracked, and therefore, the appropriate number of results expected can be determined automatically and dynamically. Therefore, despite dynamic changes in topology, completion can be determined without awareness of the processes that create the results.

Determining completion of transactions processing in a dynamically changing network

Resource contention monitoring and analysis are provided for a single system or multi-system environment. Resource contention is tracked at a task level when contention occurs by listing each owner of a resource in a blocker list and each waiter for the resource in a waiter list. Each list is ordered oldest to newest so each instance of contention is added to the end of the respective list. The resource request and contention lists are cross-linked to provide easy coordination between the resource queues and the contention lists. Techniques for analyzing contention using the lists, including deadlock analysis, are described.

Resource contention analysis employing time-ordered entries in a blocking queue and waiting queue

Resource contention monitoring employing time-ordered entries in a blocking queue and waiting queue

Method and system for processing messages in a distributed computing

A method and apparatus for serializing a request for access to a resource originating from a requester in a system of a multisystem complex. Each system of the complex maintains local contention data indicating contention between requesters on that system for access to the resource, as well as a local contention summary summarizing the local contention data. A global manager for managing contention between the systems uses the local contention summaries to determine the existence of global contention for the resource. In response to a request for access to the resource originating from a requester on a system, the system determines whether the request requires an update of the local contention summary for the system. If the request does not require an update of the local contention summary, the system processes the request in accordance with the local contention data for the system. If the request does require an update of the local contention summary, the system notifying the global manager of the update and processing the request in accordance with the response received from the global manager.

Method and apparatus for serializing resource access requests in a

A computer complex is provided with a mechanism for message delivery and redelivery in a controlled manner through the use of distributed shared memory. This provides a mechanism for overall computer system complex operation from a plurality of consoles which are registered or identified to the system and which particularly enhances capabilities for remote operation. In this way the complex can be made to look like a single system. Direct communication between any pair of systems is provided, say, by channel-to-channel adapters. Message information is maintained in each system which can also communicate with shared storage to establish update level information regarding locally maintained message information.

Multicomputer complex having a distributed shared memory system for

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Poughkeepsie, NY, United States of America

Scott Andrew Fagen