proximately equal to the ratio of the used CPU measured HyperV to the available CPU (host view not guest view) per VM Relationship with vCPU usage: virtual CPU usage = (approx)usagemhz / (# of virtual CPUs X core frequency) This measurement has been certified available for Xen hypervisors as of July 14, 2016. TABLE 16.2 Ceilometer Memory Counters OpenStack Ceilometer Measurement Description Level Parameter Amount of all physical memory actively used by the powered-on VMs as VM layer estimated by VM kernel based on recently accessed memory pages Amount of all physical memory consumed by powered-on VM for guest VM level memory.resident or memory (aka, amount of machine memory used on the host by that VM) memory.usage in Libvirt Current amount of guest physical memory swapped out to the virtual VM level machine's swap file by the VMkernel Amount of memory allocated by VM memory control driver VM level (vmmemctl). Amount of guest physical memory currently reclaimed from VM through ballooning Sum of all machine memory allocated to powered-on VMs above VM level reserved amount 16.8 NFV DATA MEASUREMENT FRAMEWORK In AT&T's vision, virtualized network functions are expected to be instantiated in a significantly dynamic manner that requires the ability to provide real-time responses to actionable events from virtualized resources as well as end-user transactions. NFV lifecycle management (including instantiation, scale-out/in, performance measurements, event correlation, termination, reboots, etc.) requires granular and accurate measurements at the tenant and infrastructure level. Operators need a passive and active measurement framework to gather key performance, usage, telemetry, and events from the dynamic, multivendor virtualized infrastructure in order to compute various ana- lytics and respond with appropriate actions based on any observed anomalies or significant events. 16.8.1 ORGANIC NFV DATA MEASUREMENT MODEL To realize the full benefits of NFV, it is important for network operators to be able to auto- mate the 