With the increasing demand for big data processing and faster memory databases, such as SAP HANA, the demand for large-size virtual machines is getting stronger. Meanwhile, for enterprise virtualization and private cloud scenarios (such as VSI), virtual machine density improvement is also an important means of saving cost, that is, CPU over-commitment. In this session, we will share some optimization ways in virtualization on the KVM platform for public and/or private cloud. The first one is for the optimization of the spinlock holder of the guest, so that we can improve the synchronization efficiency between the VCPUs of the large-scale virtual machine. The second one is the "balance scheduler", as far as possible to ensure that different VCPUs of the same virtual machine can be scheduled at the same time to improve performance. The last one is optimization of the RTC clock compensation scheme is moved from userspace to kernel to reduce overhead of context switching and increase the density of Windows virtual machines in the private cloud.
