A method, system and computer program product are provided for implementing dynamic configuration of a Single Root Input/Output Virtualization (SRIOV) virtual function in a virtualized system. A management function, a hypervisor, a hypervisor based PF device driver and a partition based virtual function (VF) device driver are used to implement usage based VF resizing. The management function periodically queries the SRIOV adapter for activity statistics for every assigned virtual function. The management function builds a usage heuristic based on these statistics and calculates VF resource usage based on these statistics. The usage information determines whether VF resources need to be scaled-up or scaled-down. A corresponding resize event is generated and send by the management function to both the hypervisor based PF device driver and partition based VF device driver. Both the PF and VF device drivers scale to the corresponding VF resource of the resize event.