What I mean is that ACPI is required nowadays for any sane SMP. Yes, enabling ACPI.
Speaking of 200% CPU for "MPS" being faster than ACPI version - maybe it's your cpufreq code, and switching from 'ondemand' to 'performance' governer will make ACPI version faster? I see no difference in speed between ACPI and non-ACPI version of a _single_-CPU winXP, and my winXP does not boot at all (BSOD) with -smp 2 and -no-acpi. I never tried to find out why, because felt it's not the right way anyway (and it shows similar BSOD when wrongly switching between ACPI and non-ACPI in winXP on many older (PIII etc) - again, non-smp - boxes). /mjt -- Windows XP uses 200% CPU when given 2 VCPUs https://bugs.launchpad.net/bugs/654913 You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. Status in QEMU: New Bug description: When using libvirt to give a domain 2 CPUs (<domain type='kvm'><vcpu>2</vcpu></domain>), the Windows XP kvm process will use 200% CPU when Windows is idle. Switching the number of CPUs back to 1, the kvm process gives normal idle percentages. Using libvirt 0.8.3-1ubuntu9, tried with the following qemu-kvm packages: qemu-kvm_0.12.4+noroms-0ubuntu7_amd64.deb qemu-kvm_0.12.5+noroms-0ubuntu4_amd64.deb The smp flag being set by libvirt is: -smp 2,sockets=2,cores=1,threads=1
