A Simple Cache Partitioning Approach in a Virtualized Environment

Abstract

Virtualization is often used in systems for the purpose of offering isolation among applications running in separate virtual machines (VM). Current virtual machine monitors (VMMs) have done a decent job in resource isolation in memory, CPU and I/O devices. However, when looking further into the usage of lower-level shared cache, we notice that one virtual machine’s cache behavior may interfere with another’s due to the uncontrolled cache sharing. In this situation, performance isolation cannot be guaranteed. This paper presents a cache partitioning approach which can be implemented in the VMM. We have implemented this mechanism in Xen VMM using the page coloring technique traditionally applied to the OS. Our VMM-based implementation is fully transparent to the guest OSes. It thus shows the advantages of simplicity and flexibility. Our evaluation shows that our cache partitioning method can work efficiently and improve the performance of co-scheduled applications running within different VMs. In the concurrent workloads selected from the SPEC CPU 2006 benchmarks, our technique achieves a performance improvement by up to 19% for the most sensitive workloads