Host Windows 2019 server, a VM on host 99% CPU

Question

- <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
- <System>
  <Provider Name="Microsoft-Windows-WHEA-Logger" Guid="{c26c4f3c-3f66-4e99-8f8a-39405cfed220}" /> 
  <EventID>2</EventID> 
  <Version>0</Version> 
  <Level>3</Level> 
  <Task>0</Task> 
  <Opcode>0</Opcode> 
  <Keywords>0x8000000000000002</Keywords> 
  <TimeCreated SystemTime="2023-05-21T01:58:21.703565000Z" /> 
  <EventRecordID>83117699</EventRecordID> 
  <Correlation ActivityID="{f99b800c-d922-427e-b58f-c83741b3e29c}" /> 
  <Execution ProcessID="2104" ThreadID="3164" /> 
  <Channel>System</Channel> 
  <Computer>VMPOSSUM</Computer> 
  <Security UserID="S-1-5-19" /> 
  </System>
- <EventData>
  <Data Name="Length">880</Data> 
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  </EventData>
  </Event>

Answer 1

Hi.

Please refer to this document for high CPU troubleshooting:

https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/troubleshoot-high-cpu-issues-azure-windows-vm

Hope the information is helpful.

Answer 2

Hello there,

Did you upgrade your cluster from 2016 to 2019?

This is a problem with Hyper-Threading when you upgrade your cluster from 2016 to 2019. You need to make sure to upgrade your VM's configuration version when the VM's are off from 8.0 to 9.0. You may also need to set the VM Processor settings to HwThreadCountPerCore to 0 from 1.

In Windows Server 2019, Hyper-V now defaults to a more secure “core scheduler” where previous versions used “classic scheduler” for CPU scheduling and isolation. What this means, is that when you migrate a VM over to Hyper-V on WS2019, you need to update the VM configuration and change some settings, or it will only use a single hardware thread per core.

Get-VMHostSupportedVersion

Get-VM | FT Name, Version

Get-VM | Update-VMVersion

Get-VM | Get-VMProcessor | FT VMName,HwThreadCountPerCore

Get-VM | Set-VMProcessor -HwThreadCountPerCore 0

Hope this resolves your Query !!

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