A Performance Benchmarking Analysis of Hypervisors Containers and Unikernels on ARMv8 and x86 CPUs.

Network Functions Virtualization paradigm has emerged as a new concept in networking which aims at cost reduction and ease of network scalability by leveraging on virtualization technologies and commercial-off-the-shelf hardware to disintegrate the software implementation of network functions from the underlying hardware. Recently, lightweight virtualization techniques have emerged as efficient alternatives to traditional Virtual Network Functions (VNFs) developed as VMs. At the same time ARMv8 servers are gaining traction in the server world, mostly because of their interesting performance per watt characteristics. In this paper, the CPU, memory and Input/Output (I/O) performance of such lightweight techniques are compared with that of classic virtual machines on both x86 and ARMv8 platforms. More in particular, we selected KVM as hypervisor solution, Docker and rkt as container engines and finally Rumprun and OSv as unikernels. On x86, our results for CPU and memory related workloads highlight a slightly better performance for containers and unikernels whereas both of them perform almost twice as better as KVM for network I/O operations. This highlights performance issues of the Linux tap bridge with KVM but that can easily be overcome by using a user space virtual switch such as VOSYSwitch and OVS/DPDK. On ARM, both KVM and containers produce similar results for CPU and memory workloads, but have an exception for network I/O operations where KVM proves to be the fastest. We also showcase the several shortcomings of unikernels on ARM which account for their lack of stable support for this architecture.