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  • 1.  CPU Ready vs CPU Wait

    Posted Aug 20, 2013 08:50 PM

    Hi Guys,

    Can somebody explain the difference between these two metrics? I'm really struggling to find the difference. I have some VMs that are running badly and seeing about 40% CPU wait time (not ready time!).

    Many thanks in advance.

    Mr G



  • 2.  RE: CPU Ready vs CPU Wait

    Broadcom Employee
    Posted Aug 21, 2013 04:50 AM

    Ok wait is a tricky one which can mean nothing but can mean something is wrong.

    basically %wait + %rdy + %cstp + %run = 100%

    %RDY is the amount of time the virtual machine is ready to use a pCPU but has to wait to get time on it.

    %Wait is the amount of time its waiting on the VMKernel resource. %wait also include %idle so the way I look at it is %WAIT - % IDLE = total time waiting on IO resources (this could be from disk/network etc)

    So if %IDLE basically equals %WAIT then everything is fine, as idle is just that the VM is not doing anything.