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Excessive usage of physical CPU resources by the RHEV hypervisor or its VMs can be the source of prolonged slowdowns that may be experienced by those VMs. Hence, whenever users complaint of slowdowns in their virtual applications, it would be best to first check whether the hypervisor has adequate unused CPU resources, as a CPU contention can have a disastrous effect on VM performance and consequently application performance. This is why, the eG agent, with the help of its RHEVHostProcTest, runs periodic usage checks on the CPU resources of the hypervisor. Besides proactively detecting abnormal CPU consumption by the hypervisor, the test also accurately points you to the root-cause of the CPU contention - did it happen because of CPU-hungry VMs on the hypervisor? did it happen because of CPU-hungry user processes or system-level processes? did it occur when the hypervisor performed Kernel Same-Page Merging? or did it happen when the CPU was idle?

Measurement	Description	Measurement Unit	Interpretation
User_cpu_util	Indicates the percentage of physical CPU used by the user processes in this RHEV hypervisor.	%	AComparing the value of these measures will enable administrators to figure out where the hypervisor is spending the maximum CPU time - in processing user requests? in system-level processes? or when being idle?
Sys_cpu_util	Indicates the percentage of CPU resources that the hypervisor utilized for system-level processing.	%
Idle_cpu_util	Indicates the percentage of CPU time utilized when the hypervisor was idle.	%
Cpu_util	Indicates the percentage of CPU utilized by the hypervisor.	%	A high value of this measure is a cause for concern, as it indicates excessive CPU usage by the hypervisor. If left unchecked, it may cause a serious contention for CPU resources amidst VMs. Use the detailed diagnosis of this measure to know which VMs on the hypervisor are consuming the CPU resources excessively.
Krnl_pageMrg_util	Indicates the percentage of CPU time spent by the hypervisor when performing Kernel Same-page Merging (KSM).	%	KMemory page sharing is supported through a kernel feature called Kernel Same-page Merging (KSM). KSM scans the memory of each virtual machine and where virtual machines have identical memory pages KSM merges these into a single page that is shared between the virtual machines, storing only a single copy. If a guest attempts to change this shared page it will be given it's own private copy. When consolidating many virtual machines onto a host there are many situations in which memory pages may be shared - for example unused memory within a Windows virtual machine, common DLLs, libraries, kernels or other objects common between virtual machines. With KSM more virtual machines can be consolidated on each host, reducing hardware costs and improving server utilization. Use this measure to determine how CPU-intensive KSM is.