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Configuration/Setup instructions can be found here:  CPU Utilisation case study Configuration

The idea behind this wiki is to look at the CPU metrics from the baremetal host, the hypervisor and the VM itself to see the if the CPU utilisation metrics reported are consistent across all 3.

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Two tests were conducted. One without isolating cpus from the OS and one with isolating CPUs from the OS on the baremetal host and pinning the vCPUs to those isolated cores. Results for the unisolated tests as expected have some unusual results... 

The CPU plugins for collectd were configured not to report the CPU meterics per state - so just a single metric for utilization

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               (time_diff_sec * node_cpus * NANOSEC_IN_SEC);

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With Isolation (

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stress test test, 1 second interval)

Core 10 and 11 were isolated from the OS using the isolcpus argument to grub command line and using virsh to Pin the vCPUs to those cores:

$ virsh vcpupin test 0 10

$ virsh vcpupin test 1 11

$ virsh vcpupin test

VCPU: CPU Affinity

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   0: 10

   1: 11

With Isolation (stress test test, 10 second interval)

Note: stress was ran for 20 seconds in this case

With Isolation (idle test)

Without Isolation (idle test)

Without Isolation (idle test)