Methods, parallel computers, and products are provided for identifying
messaging completion on a parallel computer. The parallel computer
includes a plurality of compute nodes, the compute nodes coupled for data
communications by at least two independent data communications networks
including a binary tree data communications network optimal for
collective operations that organizes the nodes as a tree and a torus data
communications network optimal for point to point operations that
organizes the nodes as a torus. Embodiments include reading all counters
at each node of the torus data communications network; calculating at
each node a current node value in dependence upon the values read from
the counters at each node; and determining for all nodes whether the
current node value for each node is the same as a previously calculated
node value for each node. If the current node is the same as the
previously calculated node value for all nodes of the torus data
communications network, embodiments include determining that messaging is
complete and if the current node is not the same as the previously
calculated node value for all nodes of the torus data communications
network, embodiments include determining that messaging is currently
incomplete.