High CPU Contention issue

[veel84]

I have an issue with high CPU Contention which sometimes averages above 10% for a good portion of the day but I cannot seem to get it down below 5%.

Here's the basic setup, it runs on ESXi 6.0.0 build 3568940.

Here is what is on each of the two hosts:

Here is CPU Contention according to vRealize for today:

Now according to me, i have plenty of free pCPU's to account for scheduling of all my vCPU's so in theory I should not be experiencing this much CPU Contention. I do have two other clusters that work harder than this one and they rarely spike above 2.5%. Anything else i need to look into?

[sxnxr]

The first thing to check is what your CPU power profile is set to in you BIOS If it is not set to high performance then you can get high contention when the cpu is put into power saving mode. I have also had to upgrade the firmware on the hosts from time to time due to a bug that was causing the cpus not to be running at high performance even tho it was set. You can check what the power policy is set to in  configuration -> power management (the one under hardware)

[veel84]

I had this in my checklist already but I kept checking the one under software, thank you for the reply! Looks like my policy is set to Balanced, I made the change to high performance.

[sunnydua2011101]

You might seen high contention if the VM is over sized from a vCPU or RAM perspective. Rightsizing is another way by which you can reduce contention.

[veel84]

That did not help, its still hitting well above 10 for hours on at times.

[sunnydua2011101]

What is the version of vSphere you are using and is the VM doing a lot of Network or Storage I/O??

[jengl]

Hey veel84,

we had the same problem in our enviromnent and fixed it by setting the BIOS power management setting to OS DPM (see: Troubleshooting high VM % CPU Contention in vROps) and the power management setting for the ESXi to High performance.

This lowered the CPU latency (visible through ESXTOP or performance charts of the ESXi host), which is a part of the CPU contention metric inside vROPS.

Regards,

jengl