How much of a performance does using QEMU virtualization incur on Windows?

vfclists asked:

How much of a performance does using QEMU virtualization incur on a Windows host, when both the host and vm are running the same CPU?
Older articles indicate that using kqemu avoided the slow down in performance if both host and vm used the same instruction set. But it seems that kqemu is not used much recently or is not available for 64 bit systems.

Are more recent versions capable of maintaining performance without the use of `kqemu’?

My answer:


On a Windows host, qemu isn’t actually a hypervisor, but is doing full machine emulation with dynamic translation, which is horrendously slow, and there’s little that can be done to speed it up.

It’s maybe useful as a demonstration or for debugging purposes, but for anything serious you will want to use an actual Windows hypervisor such as Hyper-V, or some other actual hypervisor entirely (e.g. KVM on Linux).


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