Patent ID: 8219725

Claim:
A method for handling inbound initiatives in an input/output (I/O) subsystem of a multi-node computer system, wherein in each node, a plurality of I/O processors communicate with I/O devices, via a plurality of I/O paths corresponding to said plurality of nodes, and wherein said initiatives are generated by I/O hardware and/or firmware addressed by a precedent I/O request issued by a respective one of said I/O processors, and wherein said initiatives are to be processed by one or by a group of said multiple I/O processors, the method comprising: using at least one pre-defined, first data element indicating incoming or existing initiatives from any I/O path of all of said nodes and to be served by one of said I/O processors; using a plurality of second data structures, one of said second structures per I/O processor group, wherein each of said second data structures defines which initiative is preferably handled by which I/O processor or group of processors, respectively; using a plurality of third data structures, one of said third structures per I/O processor group, wherein multiple bits can be set in order to indicate the occurrence of respective initiatives for respective multiple I/O processors; and repeatedly balancing the workload between the groups of I/O processors by distributing initiatives to other groups of I/O processors in addition to the preferred group.