CompSC: Live Migration with Pass-through Devices

Live migration is one of the most important features of virtualization technology. With regard to recent virtualization techniques, performance of network I/O is critical. Current network I/O virtualization (e. g. Para-virtualized I/O, VMDq) has a significant performance gap with native network I/O. Pass-through network devices have near native performance, however, they have thus far prevented live migration. No existing methods solve the problem of live migration with pass-through devices perfectly. In this paper, we propose CompSC: a solution of hardware state migration that will enable the live migration support of pass-through devices. We go on to apply CompSC to SR-IOV network interface controllers. We discuss the attributes of different hardware states in pass-through devices and migrate them with corresponding techniques. Our experiments show that CompSC enables live migration on an Intel 82599 VF with a throughput 282.66% higher than para-virtualized devices. In addition, service downtime during live migration is 42.9% less than para-virtualized devices.