> Note that even OS kernels can have this issue - imagine what happens in virtualized environments with overcommitted physical CPU's scheduled by a hypervisor as virtual CPU's? Yeah - exactly. Don't do that. Or at least be aware of it, and have some virtualization-aware paravirtualized spinlock so that you can tell the hypervisor that "hey, don't do that to me right now, I'm in a critical region".

I can't be the only one who learned this the hard way by cramming too many vCPUs onto too few physical cores and initially wondering where the high load and latencies came from.