I am seeing horrible cpu usage from my windows 10 vm that has 4 physical and 8 logical cores assigned along with 8GB or RAM.

The cpu is a x3950 xml shown below.

 

<?xml version='1.0' encoding='UTF-8'?>
<domain type='kvm'>
  <name>DL</name>
  <uuid>cce2c555-cb61-0412-06bc-7ffb50430328</uuid>
  <description>Win10</description>
  <metadata>
    <vmtemplate xmlns="unraid" name="Windows 10" icon="windows.png" os="windows10"/>
  </metadata>
  <memory unit='KiB'>8388608</memory>
  <currentMemory unit='KiB'>8388608</currentMemory>
  <memoryBacking>
    <nosharepages/>
  </memoryBacking>
  <vcpu placement='static'>8</vcpu>
  <cputune>
    <vcpupin vcpu='0' cpuset='4'/>
    <vcpupin vcpu='1' cpuset='20'/>
    <vcpupin vcpu='2' cpuset='5'/>
    <vcpupin vcpu='3' cpuset='21'/>
    <vcpupin vcpu='4' cpuset='6'/>
    <vcpupin vcpu='5' cpuset='22'/>
    <vcpupin vcpu='6' cpuset='7'/>
    <vcpupin vcpu='7' cpuset='23'/>
  </cputune>
  <os>
    <type arch='x86_64' machine='pc-q35-4.2'>hvm</type>
    <loader readonly='yes' type='pflash'>/usr/share/qemu/ovmf-x64/OVMF_CODE-pure-efi.fd</loader>
    <nvram>/etc/libvirt/qemu/nvram/cce2c555-cb61-0412-06bc-7ffb50430328_VARS-pure-efi.fd</nvram>
  </os>
  <features>
    <acpi/>
    <apic/>
  </features>
  <cpu mode='host-passthrough' check='none'>
    <topology sockets='1' cores='4' threads='2'/>
    <cache mode='passthrough'/>
    <feature policy='require' name='topoext'/>
  </cpu>
  <clock offset='localtime'>
    <timer name='rtc' tickpolicy='catchup'/>
    <timer name='pit' tickpolicy='delay'/>
    <timer name='hpet' present='no'/>
    <timer name='hypervclock' present='yes'/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <devices>
    <emulator>/usr/local/sbin/qemu</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw' cache='writeback'/>
      <source file='/mnt/user/domains/DL/vdisk1.img'/>
      <target dev='hdc' bus='virtio'/>
      <boot order='1'/>
      <address type='pci' domain='0x0000' bus='0x03' slot='0x00' function='0x0'/>
    </disk>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw' cache='writeback'/>
      <source file='/mnt/user/domains/DL/vdisk2.img'/>
      <target dev='hdd' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x04' slot='0x00' function='0x0'/>
    </disk>
    <controller type='pci' index='0' model='pcie-root'/>
    <controller type='pci' index='1' model='pcie-root-port'>
      <model name='pcie-root-port'/>
      <target chassis='1' port='0x10'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0' multifunction='on'/>
    </controller>
    <controller type='pci' index='2' model='pcie-root-port'>
      <model name='pcie-root-port'/>
      <target chassis='2' port='0x11'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x1'/>
    </controller>
    <controller type='pci' index='3' model='pcie-root-port'>
      <model name='pcie-root-port'/>
      <target chassis='3' port='0x12'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x2'/>
    </controller>
    <controller type='pci' index='4' model='pcie-root-port'>
      <model name='pcie-root-port'/>
      <target chassis='4' port='0x13'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x3'/>
    </controller>
    <controller type='virtio-serial' index='0'>
      <address type='pci' domain='0x0000' bus='0x02' slot='0x00' function='0x0'/>
    </controller>
    <controller type='sata' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x1f' function='0x2'/>
    </controller>
    <controller type='usb' index='0' model='qemu-xhci' ports='15'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </controller>
    <interface type='bridge'>
      <mac address='52:54:00:22:b2:c6'/>
      <source bridge='br0'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
    </interface>
    <serial type='pty'>
      <target type='isa-serial' port='0'>
        <model name='isa-serial'/>
      </target>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>
    <channel type='unix'>
      <target type='virtio' name='org.qemu.guest_agent.0'/>
      <address type='virtio-serial' controller='0' bus='0' port='1'/>
    </channel>
    <input type='tablet' bus='usb'>
      <address type='usb' bus='0' port='1'/>
    </input>
    <input type='mouse' bus='ps2'/>
    <input type='keyboard' bus='ps2'/>
    <graphics type='vnc' port='-1' autoport='yes' websocket='-1' listen='0.0.0.0' keymap='en-us'>
      <listen type='address' address='0.0.0.0'/>
    </graphics>
    <video>
      <model type='qxl' ram='65536' vram='65536' vgamem='16384' heads='1' primary='yes'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0'/>
    </video>
    <memballoon model='virtio'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/>
    </memballoon>
  </devices>
</domain>

I have noticed this is an ongoing issue with KVM and windows 10 vm's as seen from thee links below.

 

https://serverfault.com/questions/955439/why-windows-10-virtual-machine-show-high-cpu-load-on-kvm-hyprvisor

https://forum.proxmox.com/threads/high-cpu-load-for-windows-10-guests-when-idle.44531/#post-213876

https://bugs.launchpad.net/qemu/+bug/1775702

https://askubuntu.com/questions/1033985/kvm-high-host-cpu-load-after-upgrading-vm-to-windows-10-1803

 

enabling hpet and hypervclock did settle it down a little bit but still nothing like the others.

I am struggling trying to enable 

<synic state='on'/>

<stimer state='on'/>

as every time i go into the xml and enter this in it gets wiped after i save it, has anyone else run into this issue?

 

Here is another link that shows all of these hyperv options availible

https://github.com/qemu/qemu/blob/master/docs/hyperv.txt

 

 

When you say "horrible CPU usage" are you referring to idle usage, or problems in normal operation?

 

I had idle usage of 10-15% and I had to set <timer name='hpet' present='yes'/> (you have it set to 'no') to get it to drop down to 0-1% at idle.  In a previous VM, I also had to delete unused USB root hubs in the VM device manager.

 

I don't see any hyper-v settings enabled in your XML.  You need those for stimer, etc.  

 

My xml for comparison

 

  <features>
    <acpi/>
    <apic/>
    <hyperv>
      <relaxed state='on'/>
      <vapic state='on'/>
      <spinlocks state='on' retries='8191'/>
      <vendor_id state='on' value='none'/>
    </hyperv>
  </features>
  <cpu mode='host-passthrough' check='none'>
    <topology sockets='1' cores='4' threads='1'/>
  </cpu>
  <clock offset='localtime'>
    <timer name='hypervclock' present='yes'/>
    <timer name='hpet' present='yes'/>
  </clock>

 

Edited March 14, 20206 yr by toastman

1 minute ago, toastman said:

When you say "horrible CPU usage" are you referring to idle usage, or problems in normal operation?

 

I had idle usage of 10-15% and I had to set <timer name='hpet' present='yes'/> (you have it set to 'no') to get it to drop down to 0-1% at idle.  In a previous VM, I also had to delete unused USB root hubs in the VM device manager.

 

I don't see any hyper-v settings enabled in your XML.  You need those for stimer, etc.  

Yes I am just referring to idle usage, in the vm settings if i enable hyper-v it goes away after i save, same goes for if i add it to the xml manually.

 

I did end up enabling hpet and it helped a little, I haven't tried deleting unused USB root hubs yet but i did switch it over to usb 3.0 and it seemed to take them all away.

11 minutes ago, Bigjohns97 said:

Yes I am just referring to idle usage, in the vm settings if i enable hyper-v it goes away after i save, same goes for if i add it to the xml manually.

 

I did end up enabling hpet and it helped a little, I haven't tried deleting unused USB root hubs yet but i did switch it over to usb 3.0 and it seemed to take them all away.

You have to start a new template to change Hyper-V state.