CPU Ready vs CPU Wait

[Mr_G_Grant]

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

[NuggetGTR]

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.