[Qemu-devel] [Bug 1318830] Re: High CPU usage on windows virtual machine

[Ryan Harper]

Hi,

Are you running ntp in the host or timekeeping in the guest?  If so, is
the guest clock close to what current time should be?

Also, can you try adding this option:

-global mc146818rtc.lost_tick_policy=slew

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https://bugs.launchpad.net/bugs/1318830

Title:
  High CPU usage on windows virtual machine

Status in QEMU:
  New
Status in qemu package in Ubuntu:
  New

Bug description:
  I got Ubuntu 14.04, with Qemu 2.0 and moved my windows VM to this new box, 
and made sure that what this article indicates was achieved
  https://www.kraxel.org/blog/2014/03/qemu-and-usb-tablet-cpu-consumtion/
  I can attest that it works following the instructions, erasing the registry, 
etc.
  Unfortunately, with 4 cpus as below, I still see 60% CPU outside as shown by 
"Top" versus 0% CPU inside. My Kernel is 3.15.0-031500rc4-generic
  If some developer wants to log in and take a look, I am happy to help. The 
box is not in production and I take full responsibility. Until this is solved, 
KVM is not going to compete with Hyper-V or Vmware.  Basically KVM is not 
suitable for the Enterprise as of yet.

  qemu-system-x86_64 -enable-kvm -name Production -S -machine pc-
  i440fx-2.0,accel=kvm,usb=off -cpu
  
kvm64,+rdtscp,+pdpe1gb,+x2apic,+dca,+pcid,+pdcm,+xtpr,+tm2,+est,+smx,+vmx,+ds_cpl,+monitor,+dtes64,+pclmuldq,+pbe,+tm,+ht,+ss,+acpi,+ds,+vme,hv_relaxed,hv_vapic,hv_spinlocks=0xfff
  -m 4024 -realtime mlock=off -smp 4,sockets=1,cores=4,threads=1 -uuid
  e8701c5c-b542-0199-fd2a-1047df24770e -no-user-config -nodefaults
  -chardev
  
socket,id=charmonitor,path=/var/lib/libvirt/qemu/Production.monitor,server,nowait
  -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime
  -no-shutdown -boot strict=on -device piix3-usb-
  uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive
  file=/var/lib/libvirt/images/Production.img,if=none,id=drive-virtio-
  disk0,format=raw -device virtio-blk-
  pci,scsi=off,bus=pci.0,addr=0x6,drive=drive-virtio-disk0,id=virtio-
  disk0,bootindex=1 -netdev tap,fd=30,id=hostnet0,vhost=on,vhostfd=31
  -device virtio-net-
  pci,netdev=hostnet0,id=net0,mac=00:16:3a:d2:cd:ea,bus=pci.0,addr=0x3
  -netdev tap,fd=35,id=hostnet1,vhost=on,vhostfd=36 -device virtio-net-
  pci,netdev=hostnet1,id=net1,mac=52:54:00:70:fe:54,bus=pci.0,addr=0x4
  -chardev pty,id=charserial0 -device isa-
  serial,chardev=charserial0,id=serial0 -device usb-tablet,id=input0
  -vnc 127.0.0.1:0 -device VGA,id=video0,bus=pci.0,addr=0x2 -device
  intel-hda,id=sound0,bus=pci.0,addr=0x5 -device hda-
  duplex,id=sound0-codec0,bus=sound0.0,cad=0 -device virtio-balloon-
  pci,id=balloon0,bus=pci.0,addr=0x7

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