Nested lab tip (using VMware Workstation)

[richard612]

I recently noticed something when trying to resolve a stability issue with my nested lab setup (ESXi 5.1 inside Workstation 10).  The "Package C-states" setting in my motherboard BIOS has an impact on the idle CPU utilization of my ESX hosts.  The nested ESX hosts were hovering around 15% CPU for no apparent reason.  ESXTOP reflected the 15% CPU usage but all running processes were under 1-2% total.  Odd.  Now my ESX installs are at 1% (with no nested VMs running).

Worth a look if you have a nested lab setup.  I also had to disable "report C6" and disable "enhanced C1 (C1E)" to make everything stable.

Has anyone else seen this kind of behavior?

[0v3rc10ck3d]

Yep, I've run into a lot of issues in production environments (not nested) as a result of power state options. The fix is usually setting everything to high performance.

When the system is switching between states there is latency introduced, additionally if you have a host with 8 physical core's available, and there's a VM with 1 proc hitting 100% the board might think that technically the physical CPU isn't working very hard and adjust c states which will impact performance on that VM.

Here's an interesting link on it: VMware KB: Poor virtual machine application performance may be caused by processor power management ...

[richard612]

I just found another error from WHEA-Logger (Event ID 19).  I disabled C7...  We'll see if that helps.

So far my CPU operating temp hasn't changed.  It will definitely ramp up if I disable ALL power mgmt settings; the CPU will idle around 65C instead of the usual 42C.  Speedstep is an important one from a power savings perspective; hopefully I can keep it.