Research on necessity of adjusting PLE configuration

Virtualization is important in server consolidation and essential for cloud computing. Using virtualization technology, a single physical machine can provide multiple isolated virtual machine to users, which will improve the overall system resources usage. However, virtualization will also introduce new challenges and mechanisms that work functionally in traditional operating system may lead to the performance degradation of virtual machines. LHP problem arises because spin lock mechanism could not work effectively in virtualization environment. To solve LHP problem, many solutions have been proposed to reduce its performance impact on virtual machines and improve the overall system performance. A hardware assisted technology called Pause Loop Exit(PLE) has been proposed to help detecting spin lock waiter in virtual machines and then reduce the cpu time used in spinning. In this paper, we verify the necessity of adjusting PLE configuration in different scenarios. Our experiment results show that it is necessary to adjust PLE configuration when the virtual machine is running different applications and the number of virtual machines varies.