3 ms·
Most hypervisors make this information available to the guest, you can see it as st% in top for example.
by the8472 7y ago
Most hypervisors make this information available to the guest, you can see it as st% in top for example.
- xxpor 7y agoJust to expand the abbreviation: steal time percentage It's important to know for the OS because otherwise your clock will be way off. There's probably other issues that would pop up too that I'm just forgetting right now.
- saagarjha 7y agoWouldn't this only be detectable to a guest that's aware it's being virtualized (that is, a paravirtualized one?)
- tryauuum 7y agoI have an impression that terms "paravirtualization" and "full virtualization" are fuzzy nowadays. KVM, for example, reports steal time. Yet, KVM is considered to be full virtualization. Also, guest can still guess that it is a mere guest by looking into loaded drivers. Many drivers, like virtio-blk, inevitably lead to conclusion that environment is virtualized, no matter what cpu says.
- tryauuum 7y agoI might be wrong, but I think "paravirtualized" means that you don't have to modify your kernel to work with virtual CPU / virtual memory. It doesn't mean "guest isn't aware it's being virtualized"
- detaro 7y agoParavirtualization means that the virtualization does not entirely pretend to be real hardware, but has special interfaces that require OS modifications or special drivers to use (although sometimes optional. E.g. KVM offers full virtualization, but also has the option of providing VirtIO devices, which you might call paravirtualization)