Category Archives: Performance


Don’t forget to set the advanced ESXi setting “Cpu.PcpuMigrateIdlePcpus” back to its default value of 4 if it was changed to 0 as a workaround for the issue described in

In over-committed CPU environments (VDI), having Cpu.PcpuMigrateIdlePcpus disabled can increase CPU Ready time. It should be set back to its default of 4 as the official patch for the issue ( states.

Here is a 6-month graph for a single host (CPU | Ready) showing the 5-month period where Cpu.PcpuMigrateIdlePcpus was disabled in mid-February and re-enabled (back to default) a few days ago:

period of high cpu ready

The setting can be changed quickly and easily across all hosts via PowerCLI: Set advanced settings on all hosts.