International Business Machines Corporation

Hung Q Thai

Hanhong Xue

Tsai-Yang Jea

Chulho Kim

Uman Chan

Deryck X Hong

Abhinav Vishnu

Zenon J Piatek

Zhi Zhang

Wen Chong Chen

Wiliam P LePera

A method, apparatus and program product utilize an empirical approach to determine the locations of one or more IO adapters in an HPC environment. Performance tests may be run using a plurality of candidate mappings that map IO adapters to various locations in the HPC environment, and based upon the results of such testing, speculative adapter affinity information may be generated that assigns one or more IO adapters to one or more locations to optimize adapter affinity performance for subsequently-executed tasks.

Empirical determination of adapter affinity in high performance computing (HPC) environment

A message flow controller limits a process from passing a new message in a reliable message passing layer from a source node to at least one destination node while a total number of in-flight messages for the process meets a first level limit. The message flow controller limits the new message from passing from the source node to a particular destination node from among a plurality of destination nodes while a total number of in-flight messages to the particular destination node meets a second level limit. Responsive to the total number of in-flight messages to the particular destination node not meeting the second level limit, the message flow controller only sends a new packet from among at least one packet for the new message to the particular destination node while a total number of in-flight packets for the new message is less than a third level limit.

Flow control for reliable message passing

Load balancing of adapters on a multi-adapter node of a communications environment. A task executing on the node selects an adapter resource unit to be used as its primary port for communications. The selection is based on the task's identifier, and facilitates a balancing of the load among the adapter resource units. Using the task's identifier, an index is generated that is used to select a particular adapter resource unit from a list of adapter resource units assigned to the task. The generation of the index is efficient and predictable.

Load balancing of adapters on a multi-adapter node

A technique for debugging code during runtime includes providing, from an outside process, a trigger to a daemon. In this case, the trigger is associated with a registered callback function. The trigger is then provided, from the daemon, to one or more designated tasks of a job. The registered callback function (that is associated with the trigger) is then executed by the one or more designated tasks. Execution results of the executed registered callback function are then returned (from the one or more designated tasks) to the daemon.

Techniques for debugging code during runtime

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