Virtual-BFQ: A Coordinated Scheduler to Minimize Storage Latency and Improve Application Responsiveness in Virtualized Systems

Abstract—Preserving responsiveness is an enabling condition for running interactive applications effectively in virtual machines. For this condition to be met, low latency usually needs to be guaranteed to storage-Input/Output operations. In contrast, in this paper we show that in virtualized environments, there is a missing link exactly in the chain of actions performed to guarantee low storage-I/O latency. After describing this problem theoretically, we show its practical consequences through a large set of experiments with real world-applications. After detailing the possible solutions to replace this missing connection, we detail our chosen solution based on the I/O scheduler BFQ (Budget Fair Queueing) named Virtual-BFQ. Which it designed to preserve a high application responsiveness in KVM (Kernel-based Virtual Machine) virtual machines on ARM architectures. For the experiments, we used two Linux schedulers, both designed t