Gnome-boxes VM taking 200% CPU while idle

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1

My gnome-boxes (qemu) Windows 10 VM is painfully slow. It is taking almost 200% CPU when idle.
It was running fine, and after some upgrade (probably kernel) it went south, and I haven’t been able to identify the cause.

top - 18:39:56 up 1 day,  8:51,  1 user,  load average: 2.20, 2.21, 2.05
Tasks: 346 total,   1 running, 345 sleeping,   0 stopped,   0 zombie
%Cpu(s):  4.7 us, 19.6 sy,  0.0 ni, 74.8 id,  0.0 wa,  0.7 hi,  0.2 si,  0.0 st
MiB Mem :  64224.6 total,  24575.3 free,  20916.7 used,  18732.6 buff/cache
MiB Swap:  12288.0 total,  12288.0 free,      0.0 used.  42037.4 avail Mem 

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND                                      
 133652 sanmi@m+  20   0   18.3g  16.2g  30860 S 195.3  25.8 280:52.81 qemu-system-x86                              
 133245 sanmi@m+  20   0  951124 288432 149848 S   3.0   0.4   0:22.75 chrome                                       
 151464 sanmi@m+  20   0 9186800 192756 100848 S   2.7   0.3   0:40.79 chrome                                       
   2357 sanmi@m+  20   0 4725420 450848 139172 S   1.7   0.7  13:52.51 gnome-shell                                  
 133523 sanmi@m+  20   0   83.0g 137760  85732 S   1.3   0.2   1:29.30 gnome-boxes                                  
 152047 sanmi@m+  20   0 4910916 135696  97756 S   1.0   0.2   0:02.72 chrome

This is the process:

[sanmi@fos ~]$ ps ax | grep qemu
 133652 ?        Rl   283:22 /usr/bin/qemu-system-x86_64 -name guest=win10,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/home/sanmi/.config/libvirt/qemu/lib/domain-1-win10/master-key.aes -machine pc-q35-4.2,accel=kvm,usb=off,dump-guest-core=off -cpu host,migratable=on -m 16390 -overcommit mem-lock=off -smp 8,sockets=1,dies=1,cores=4,threads=2 -uuid 55a45adf-ea03-4bbe-b732-396c669f802f -no-user-config -nodefaults -chardev socket,id=charmonitor,fd=27,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime,driftfix=slew -global kvm-pit.lost_tick_policy=delay -no-hpet -no-shutdown -global ICH9-LPC.disable_s3=1 -global ICH9-LPC.disable_s4=1 -boot menu=off,strict=on -device pcie-root-port,port=0x10,chassis=1,id=pci.1,bus=pcie.0,multifunction=on,addr=0x2 -device pcie-root-port,port=0x11,chassis=2,id=pci.2,bus=pcie.0,addr=0x2.0x1 -device pcie-root-port,port=0x12,chassis=3,id=pci.3,bus=pcie.0,addr=0x2.0x2 -device pcie-root-port,port=0x13,chassis=4,id=pci.4,bus=pcie.0,addr=0x2.0x3 -device pcie-root-port,port=0x14,chassis=5,id=pci.5,bus=pcie.0,addr=0x2.0x4 -device ich9-usb-ehci1,id=usb,bus=pcie.0,addr=0x1d.0x7 -device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pcie.0,multifunction=on,addr=0x1d -device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pcie.0,addr=0x1d.0x1 -device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pcie.0,addr=0x1d.0x2 -device virtio-serial-pci,id=virtio-serial0,bus=pci.2,addr=0x0 -device usb-ccid,id=ccid0,bus=usb.0,port=1 -blockdev {"driver":"file","filename":"/home/sanmi/.local/share/gnome-boxes/images/win10","node-name":"libvirt-2-storage","cache":{"direct":false,"no-flush":false},"auto-read-only":true,"discard":"unmap"} -blockdev {"node-name":"libvirt-2-format","read-only":false,"cache":{"direct":false,"no-flush":false},"driver":"qcow2","file":"libvirt-2-storage","backing":null} -device virtio-blk-pci,bus=pci.3,addr=0x0,drive=libvirt-2-format,id=virtio-disk0,bootindex=1,write-cache=on -device ide-cd,bus=ide.2,id=sata0-0-2 -netdev tap,fd=33,id=hostnet0 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:00:37:38,bus=pci.1,addr=0x0 -chardev spicevmc,id=charsmartcard0,name=smartcard -device ccid-card-passthru,chardev=charsmartcard0,id=smartcard0,bus=ccid0.0 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev spicevmc,id=charchannel0,name=vdagent -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0 -chardev spiceport,id=charchannel1,name=org.spice-space.webdav.0 -device virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=org.spice-space.webdav.0 -device usb-tablet,id=input0,bus=usb.0,port=2 -spice port=0,disable-ticketing,image-compression=off,seamless-migration=on -device qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vram64_size_mb=0,vgamem_mb=16,max_outputs=1,bus=pcie.0,addr=0x1 -device ich9-intel-hda,id=sound0,bus=pcie.0,addr=0x1b -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -chardev spicevmc,id=charredir0,name=usbredir -device usb-redir,chardev=charredir0,id=redir0,bus=usb.0,port=3 -chardev spicevmc,id=charredir1,name=usbredir -device usb-redir,chardev=charredir1,id=redir1,bus=usb.0,port=4 -chardev spicevmc,id=charredir2,name=usbredir -device usb-redir,chardev=charredir2,id=redir2,bus=usb.0,port=5 -chardev spicevmc,id=charredir3,name=usbredir -device usb-redir,chardev=charredir3,id=redir3,bus=usb.0,port=6 -device virtio-balloon-pci,id=balloon0,bus=pci.4,addr=0x0 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on
1 Like
2

This looks quite normal. The load of 2 is not an issue because that is not directly related to the cpu. Top is telling you that only 4.7% cpu time is user processes and 74.8% is idle. This link tells you a lot about what the load numbers mean and how to relate them to your system.

1 Like
3

I’m not concerned about the host machine, but take a look downwards and see the load that the qemu-system-x86 is enduring: 195.3% CPU while idle. The VM machine is barely responsive.

PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND

133652 sanmi@m+ 20 0 18.3g 16.2g 30860 S 195.3 25.8 280:52.81 qemu-system-x86

4

Post the output:

virt-host-validate
5 
[sanmi@fos ~]$ sudo virt-host-validate
  QEMU: Checking for hardware virtualization                                 : PASS
  QEMU: Checking if device /dev/kvm exists                                   : PASS
  QEMU: Checking if device /dev/kvm is accessible                            : PASS
  QEMU: Checking if device /dev/vhost-net exists                             : PASS
  QEMU: Checking if device /dev/net/tun exists                               : PASS
  QEMU: Checking for cgroup 'cpu' controller support                         : WARN (Enable 'cpu' in kernel Kconfig file or mount/enable cgroup controller in your system)
  QEMU: Checking for cgroup 'cpuacct' controller support                     : PASS
  QEMU: Checking for cgroup 'cpuset' controller support                      : WARN (Enable 'cpuset' in kernel Kconfig file or mount/enable cgroup controller in your system)
  QEMU: Checking for cgroup 'memory' controller support                      : PASS
  QEMU: Checking for cgroup 'devices' controller support                     : PASS
  QEMU: Checking for cgroup 'blkio' controller support                       : WARN (Enable 'blkio' in kernel Kconfig file or mount/enable cgroup controller in your system)
  QEMU: Checking for device assignment IOMMU support                         : PASS
  QEMU: Checking if IOMMU is enabled by kernel                               : WARN (IOMMU appears to be disabled in kernel. Add intel_iommu=on to kernel cmdline arguments)
  QEMU: Checking for secure guest support                                    : WARN (Unknown if this platform has Secure Guest support)
   LXC: Checking for Linux >= 2.6.26                                         : PASS
   LXC: Checking for namespace ipc                                           : PASS
   LXC: Checking for namespace mnt                                           : PASS
   LXC: Checking for namespace pid                                           : PASS
   LXC: Checking for namespace uts                                           : PASS
   LXC: Checking for namespace net                                           : PASS
   LXC: Checking for namespace user                                          : PASS
   LXC: Checking for cgroup 'cpu' controller support                         : FAIL (Enable 'cpu' in kernel Kconfig file or mount/enable cgroup controller in your system)
   LXC: Checking for cgroup 'cpuacct' controller support                     : PASS
   LXC: Checking for cgroup 'cpuset' controller support                      : FAIL (Enable 'cpuset' in kernel Kconfig file or mount/enable cgroup controller in your system)
   LXC: Checking for cgroup 'memory' controller support                      : PASS
   LXC: Checking for cgroup 'devices' controller support                     : PASS
   LXC: Checking for cgroup 'freezer' controller support                     : FAIL (Enable 'freezer' in kernel Kconfig file or mount/enable cgroup controller in your system)
   LXC: Checking for cgroup 'blkio' controller support                       : FAIL (Enable 'blkio' in kernel Kconfig file or mount/enable cgroup controller in your system)
   LXC: Checking if device /sys/fs/fuse/connections exists                   : PASS

Virtio-in-0.1.185 drivers and agent are installed in the Windows 10 VM

1 Like
6 
virsh dumpxml VM_NAME
8

https://pastebin.com/raw/rPjpUTkZ

1 Like
9

Check if the issue persists when you log out the guest, or boot it in the safe/recovery mode.

Also try to boot the host with 5.8 kernel:

sudo dnf downgrade kernel
sudo reboot
uname -a
10

Definitely it is kernel 5.9
safe/recovery mode under kernel 5.9 goes down to 60%, but reverting to kernel 5.8 gets back the snappy reponse to the VM and idle CPU% values down to 120%.

1 Like
11

Sorry, what do you mean?

12

I mean that under linux host kernel 5.9, the Windows 10 VM running in safe mode takes 60% CPU, but is still slow as molasses.
Under kernel 5.8, the Windows 10 VM runs as expected.

2 Likes
13

If you need virtualization, use 5.8 for the time being and test 5.10 when it is available in the testing repository, meanwhile you can report this regression against 5.9.