Live migration is a technology that seamlessly relocates a virtualized service between physical hosts, which allows services to rapidly adapt to environmental changes. Despite the large amount of research, there is still a lack of understanding of its performance. Towards a better understanding of live migration, we build a testbed and use it to migrate a computation-intensive application with docker and KVM. We evaluate the service downtime, migration time, and network usage under different conditions. The results show that KVM outperforms docker in most of the scenarios, with some critical exceptions where only docker manages to perform miaration.