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'''Description:'''
The CPU limit is the upper bound to the CPU usage for a VE. The limit is set for all CPUs the VE can execute on. That means the maximal value of the CPU limit (i.e. no limit) is the maximal limit on 1 CPU, which equals 1024, multiplied by NUM_CPUS, the number of CPUs this VM can execute on. The minimal value is 1. The CPU limit is an absolute parameter in the sense that altering the limit of one VE does not affect the limits of other VEs.
The <code>fairsched_rate()</code> system call is used to set, get, or drop (i.e. set to the maximum) CPU limit of a VE. <code>id</code> is the id of the VE. <code>op</code> can be one of the following:
In the rhel6 kernel the limit is divided between the CPUs proportionally, and a busy CPU cannot borrow time from an idle one, i.e. with a 2 CPUs container and 1024 (of 2048) limit set the usage of each CPU cannot exceed 50% in any case.
As a result, the minimal value for the limit is 1 in the rhel5 kernel and 1 * NUM_CPUS in the rhel6 kernel. If the limit value is out of the allowed range it is automatically clamped to the range.