[Bug 1914667] Re: High cpu usage when guest is idle on qemu-system-i386

[John Arbuckle]

For version 5.2 of qemu-system-i386 the instruction the guest is busy
executing over and over again is this: addb %al, (%eax)

For version 2.10.1 this is the instruction that is being executed when the 
guest is idle:
add %al,(%eax)

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https://bugs.launchpad.net/bugs/1914667

Title:
  High cpu usage when guest is idle on qemu-system-i386

Status in QEMU:
  New

Bug description:
  When running Windows XP in qemu-system-i386, the cpu usage of QEMU is
  about 100% even when the guest CPU usage is close to 2%. The host cpu
  usage should be low when the guest cpu usage is low.

  Command: qemu-system-i386 -hda <Windows XP HD image>

  Using this command also shows around 100% host CPU usage:
  qemu-system-i386 -m 700 -hda <Windows XP HD image> -usb -device usb-audio 
-net nic,model=rtl8139 -net user -hdb mountable.img -soundhw pcspk

  Using the Penryn CPU option also saw this problem:
  qemu-system-i386 -hda <Windows XP HD image> -m 700 -cpu Penryn-v1

  Using "-cpu pentium2" saw the same high host cpu usage.

  
  My Info:
  M1 MacBook Air
  Mac OS 11.1
  qemu-system-i386 version 5.2 (1ba089f2255bfdb071be3ce6ac6c3069e8012179)
  Windows XP SP3 Build 2600

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