Virtual machine scheduling for multicores considering effects of shared on-chip last level cache interference

As the cloud markets grow, the cloud providers are faced with new challenges such as reduction of power consumption and guaranteeing service level agreements (SLAs). One reason for these problems is the use of server consolidation policy based on virtualization technologies for maximizing the efficiency of resource usage. Because current virtualization technologies do not ensure performance isolation among active virtual machines (VMs), it is required to consider resource usage pattern of VMs to improve total throughput and quality of service. In this paper, we propose a virtual machine scheduler for multicore processors, which exploits the last-level cache (LLC) reference ratio. Specifically, we focus on the performance impact of contention in a shared LLC. We have found that the ratio of the number of LLC references to that of instructions (LLC reference ratio) is highly associated with the amount of cache demand, and a Performance-Maximizing VM (PMV) scheduling algorithm can be devised by using the ratio. We show that our PMV scheduler is effective by evaluation for various workloads.