Accurate energy accounting for shared virtualized environments using PMC-based power modeling techniques

Virtualized infrastructure providers demand new methods to increase the accuracy of the accounting models used to charge their customers. Future data centers will be composed of many-core systems that will host a large number of virtual machines (VMs) each. While resource utilization accounting can be achieved with existing system tools, energy accounting is a complex task when per-VM granularity is the goal. In this paper, we propose a methodology that brings new opportunities to energy accounting by adding an unprecedented degree of accuracy on the per-VM measurements. We present a system -which leverages CPU and memory power models based in performance monitoring counters (PMCs)- to perform energy accounting in virtualized systems. The contribution of this paper is twofold. First, we show that PMC-based power modeling methods are still valid on virtualized environments. And second, we introduce a novel methodology for accounting of energy consumption in virtualized systems. In overall, the results for an Intel® Core™ 2 Duo show errors in energy estimations below the 5%. Such approach brings flexibility to the chargeback models used by service and infrastructure providers. For instance, we show that VMs executed during the same amount of time, present more than 20% differences in energy consumption even only taking into account the consumption of the CPU and the memory.