Tackling the challenges of server consolidation on multi-core systems

With increasing demand to reduce system operation cost amidst growing adoption of virtualization technologies, multiple servers on a single physical chip is fast seeing typical usage in modern data centers. This trend has become more obvious with advances in system design that puts more and more multi-core CPUs into one system. As a result, it is interesting to investigate the challenges of virtualization on top of a multi-core system and the scalability of the consolidation workload on top of it. With this objective, we conduct a comprehensive analysis of an industry consolidation workload on top of a state of the art Intel system that consists of 64 physical threads. Our findings reveal that careful considerations must be taken in I/O virtualization and VM scheduling to achieve high scalability under the consolidation environment in a multi-core system. Against this backdrop, we carried out some preliminary work to demonstrate optimization opportunities. In particular, applying interrupt balance method brings in 16% performance boost whereas a finer-grained scheduler prototype added another 6% performance lift. Based on our analyses, existing VMMs should be enhanced with a) a well-designed multi-threaded I/O virtualization implementation and b) a scheduler with finer grained control on priorities.