Token-based flow control of messages in a parallel computer

An apparatus for token-based flow control of messages in a parallel computer executing a plurality of parallel operations, the parallel computer including a plurality of compute nodes, each compute node including one or more computer processors, the apparatus comprising a computer memory operatively coupled to the one or more computer processors, the computer memory having disposed within it computer program instructions that, when executed by the one or more computer processors, cause the apparatus to carry out the steps of:

• allocating, by a token administration module to a plurality of the computer processors in the parallel computer, a number of data communications tokens, wherein:
• each data communications token represents an amount of data that a computer processor may send to a destination;
• and
• the number of data communications tokens allocated to each computer processor is determined in dependence upon token distribution rules;
• identifying, by the token administration module for each computer processor, all communicators executing on the computer processor, wherein each communicator is participating in a distinct parallel operation executing on the parallel computer;
• allocating, by the token administration module to the communicators, the data communications tokens;
• determining, by a communicator attempting to send data to the destination, whether the communicator has enough available data communications tokens to send the data to the destination;
• and
• responsive to determining that the communicator has enough available data communications tokens to send the data, sending, by the communicator, the data to the destination.

A computer program product for token-based flow control of messages in a parallel computer executing a plurality of parallel operations, the parallel computer including a plurality of compute nodes, each compute node including one or more computer processors, the computer program product disposed upon a computer readable medium, the computer program product comprising computer program instructions that, when executed, cause a computer to carry out the steps of:

• allocating, by a token administration module to a plurality of the computer processors in the parallel computer, a number of data communications tokens, wherein:
• each data communications token represents an amount of data that a computer processor may send to a destination;
• and
• the number of data communications tokens allocated to each computer processor is determined in dependence upon token distribution rules;
• identifying, by the token administration module for each computer processor, all communicators executing on the computer processor, wherein each communicator is participating in a distinct parallel operation executing on the parallel computer;
• allocating, by the token administration module to the communicators, the data communications tokens;
• determining, by a communicator attempting to send data to the destination, whether the communicator has enough available data communications tokens to send the data to the destination;
• and
• responsive to determining that the communicator has enough available data communications tokens to send the data, sending, by the communicator, the data to the destination.