I mean one could say kubernetes has virtualized components, and requires VT-d extensions to operate at an accelerated speed, but I don't think containers are truly virtualized. So you can probably get away with a less than 5% benchmark if the stars aligned.
With a hypervisor you're looking at 10-15% overhead, typically. maybe getting down to 7-12% using tricks (paravirtualization, pci-passthrough etc). In my environment i am around 12% OH on a good day
i've seen way les than 10% overhead on modern hardware with sr-iov compat devices. it really depends on your network card/raid controller. some servers (and some cpus) are just not optimal for running virtualized stuff.
Indeed, standard container runtimes neither require VT-x (virtualization instructions) or VT-d (IOMMU for PCIe devices). They're "just" process isolation (cgroups), network stack isolation (netns), and filesystem isolation (overlayfs). Workloads on Kubernetes are not using virtual hardware unless you choose a managed provider or container runtime that states they are.
With a hypervisor you're looking at 10-15% overhead, typically. maybe getting down to 7-12% using tricks (paravirtualization, pci-passthrough etc). In my environment i am around 12% OH on a good day