Performance Tuning Towards a KVM-based Embedded Real-time Virtualization System
Ruhui Ma, Fanfu Zhou, Erzhou Zhu, Haibing Guan · 2013
Virtualization is a fundamental component in cloud computing because it provides numerous guest VM transparent services, such as live migration, high availabil-ity, rapid checkpoint, etc. Utilizing virtualization technology to combine real-time operating system (RTOS) and off-the-shelf time-sharing general purpose operating system (GPOS) is attracting much more interest recently. Such combination has the potential to provide a large application base, and to guarantee timely deterministic response to real-time applications, yet there remain some issues, such as respon-siveness of RTOS running on top of a virtual machine (VM), system performance and CPU resource utilization rate, etc. In this paper we propose an embedded real-time virtualization architecture based on Kernel-Based Virtual Machine (KVM), in which VxWorks and Linux are combined together. We then analyze and evaluate how KVM influences the interrupt-response times of VxWorks as a guest operat-ing system. By applying several real-time performance tuning methods on the host Linux, we will show that sub-millisecond interrupt response latency can be achieved on the guest VxWorks. Furthermore, we also find out that prioritization tuning re-sults in waste of CPU resources when RTOS is not executing real-time tasks, so we design a dynamic scheduling mechanism — co-scheduling to improve system per-formance. Experimental results with SPEC2000 and bonnie 1.4 load, show that this new architecture tuned by CPU shielding, prioritization and co-scheduling, can achieve better real-time responsiveness and system performance.