Using a decrementer interrupt to start long-running hardware operations before the end of a shared processor dispatch cycle

Systems, methods, and computer program products to perform an operation comprising processing a first logical partition on a shared processor for the duration of a dispatch cycle, issuing, by a hypervisor, at a predefined time prior to completion of the dispatch cycle, a lightweight hypervisor decrementer (HDEC) interrupt, and responsive to the lightweight HDEC interrupt, initiating an asynchronous hardware operation on the shared processor prior to completion of the dispatch cycle.