We are seeing CPU ready values at 500ms or more on almost every VM in our cluster. All VMs are only using 1 vCPU so SMP is not the issue. When looking at esxtop and CPU usage (average in percent), each of the 8 processors in the hosts average 50% usage or less. Why is the CPU usage not higher if the VMs are waiting on CPU cycles as shown in the CPU ready values? I am trying to figure out why the CPU ready values are so high.
Details:
5 hosts (8 CPUs dual-core HP DL585 G2s); ESX 4.0 build 175625; 166 VMs; DRS full auto at priority 3 or higher; 3 resource pools only using shares set to High, Medium, Low for CPU; over 600 vmotions/wk
Please let me know if you need any more info.
500 ms in 20 s period = 2.5%
This is not a problem, and 50% CPU load is not low actually.
According to VMware recommendations CPU Ready less than 5% is not an issue at all, CPU Ready is too high if more than 10%.
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MCSA, MCTS, VCP, VMware vExpert '2009
I have several VMs that average 1500 ms CPU ready time or more. I was highlighting that most or all are 500ms or higher. If the CPU ready is reaching 2000ms or more on some VMs, why am I not seeing CPU usage averages almost 75% or more on the hosts? I did find one interesting point on the CPU usage average for the hosts. On 4 of the 5 hosts in this cluster, each one has one processor that is running at 100% while the rest are around 40% each. Can anyone help me understand this?