Providing full point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer

A parallel computer for providing full point-to-point communications among compute nodes of an operational group in a global combining network, each compute node connected to each adjacent compute node in the global combining network through a link, the parallel computer comprising a plurality of computer processors and computer memory operatively coupled to the computer processors, the computer memory having disposed within it computer program instructions capable of:

• receiving a network packet in a compute node of a parallel computer, wherein the parallel computer comprises a plurality of compute nodes coupled for point-to-point data communications in a global combining network, the global combining network comprises a binary tree, each compute node is coupled to each adjacent compute node in the global combining network through a link, and the network packet specifies a destination compute node;
• selecting, in dependence upon the destination compute node, at least one of the links for the compute node along which to forward the network packet toward the destination compute node, each link comprising an exclusive, dedicated data communications connection between a single compute node and one adjacent compute node, including:
• identifying a receipt link on which the network packet was received by the compute node;
• determining whether the destination compute node is one of the adjacent compute nodes for the compute node;
• and selecting all of the links for the compute node except the receipt link if the destination compute node is not one of the adjacent compute nodes for the compute node;
• and
• forwarding the network packet along the selected link to the adjacent compute node connected to the compute node through the selected link.

A computer program product for providing full point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer, each compute node connected to each adjacent compute node in the global combining network through a link, the computer program product disposed upon a non-transitory computer readable recordable medium, the computer program product comprising computer program instructions capable of:

• receiving a network packet in a compute node of a parallel computer, wherein the parallel computer comprises a plurality of compute nodes coupled for point-to-point data communications in a global combining network, the global combining network comprises a binary tree, each compute node is coupled to each adjacent compute node in the global combining network through a link, and the network packet specifies a destination compute node;
• selecting, in dependence upon the destination compute node, at least one of the links for the compute node along which to forward the network packet toward the destination compute node, each link comprising an exclusive, dedicated data communications connection between a single compute node and one adjacent compute node, including:
• identifying a receipt link on which the network packet was received by the compute node;
• determining whether the destination compute node is one of the adjacent compute nodes for the compute node;
• and selecting all of the links for the compute node except the receipt link if the destination compute node is not one of the adjacent compute nodes for the compute node;
• and forwarding the network packet along the selected link to the adjacent compute node connected to the compute node through the selected link.