Patent ID: 7089457
Filing Date: 2006-08-08
Classification: G06F

Abstract:
1. In an enterprise-server configured with queued direct input/output (QDIO), an input-output (I/O) retry method, the method comprising: attempting a QDIO-based data transfer between outbound and inbound queues in respective sending and target logical partitions (LPARs) in the enterprise server; responsive to detecting a busy condition resulting from said attempt, determining whether said busy condition arose from an asynchronous busy condition in said target LPAR; further determining whether said busy condition arose from a synchronous busy condition; and, if it is determined that said busy condition arose from an asynchronous busy condition in said target LPAR, delaying any attempt to retry said QDIO-based data transfer, and subsequent to said delay, re-attempting said QDIO-based data transfer, but if it is determined that said failure condition arose from a synchronous busy condition, immediately and repeatedly re-attempting said QDIO-based data transfer either until said re-attempts are successful, or until said repeated re-attempts exceed a threshold limit, and, if said repeated re-attempts exceed said threshold limit, posting an error condition from which no retry can be attempted; wherein said determining step comprises the step of determining whether said synchronous busy condition arose from an inability to obtain a queue lock on said target LPAR.