Home // International Journal On Advances in Software, volume 9, numbers 1 and 2, 2016 // View article

Coordinated Task Scheduling in Virtualized Systems: Evaluation and Implementation Details

Authors:
Jérémy Fanguède
Alexander Spyridakis
Daniel Raho

Keywords: KVM/ARM; embedded virtualization; coordinated scheduling; embedded systems; task scheduling; CFS; BFS; para- virtualization

Abstract:
Task scheduling is one of the key subsystems of an operating system. Generally, by providing fairness in terms of processor time allocated to tasks, the task scheduler can guarantee low latency and high responsiveness to applications. In this paper, we demonstrate that specific problems can occur in virtualized environments, where virtual core scheduling on the host can negatively affect process scheduling in the guest. More precisely, there is a need to implement a communication channel between the host and guest task scheduler, particularly when full-virtualization techniques are used, in order to avoid latency issues and loss of responsiveness in virtual machines, especially when processors execute excessive workloads. After having analyzed the potential problems in virtual machines, experiments were performed with real world and benchmarking applications. In this work we detail possible solutions to solve the issue previously highlighted, and describe the proposed implementation, which is based on a coordinated scheduling mechanism between the host and guest systems. For testing, an embedded ARMv7 Linux-based platform and two different task schedulers were used, with a benchmark suite specifically designed for virtualized environments, with which application responsiveness and latency are measured and compared.

Pages: 107 to 115

Copyright: Copyright (c) to authors, 2016. Used with permission.

Publication date: June 30, 2016

Published in: journal

ISSN: 1942-2628