How to assign X MHz to a specific VM?

Question

How can I assign a fixed MHz value to a specific virtual machine?

Environment

OnApp Cloud (All versions)

Occasionally trying to set a specific MHz or GHz amount for a Virtual Server can be a bit confusing due to the difference in processor performance.Answer

We often have clients asking for a simple way to give a certain amount of CPU resources, such as 600MHz to a VM.

CPU cores - maximum number of cores available to a VM.
CPU priority - maximum percentage of allocated cores.

To determine how much CPU resources are available to a given VM, multiply the CPU priority by the clock speed of the physical CPU, then by CPU cores.

If you want to guarantee, for example, a 2.8GHZ single-core for a VM (on a 2.8GHz Hyper-threaded Quad-core Hypervisor), set: 

CPU cores = 1, CPU priority = 100%
(e.g. 2.8GHz * 100% = 2.8GHZ * 1 core)