I&#x27;m not sure about virtualised kernels on hypervisors working well. Under the right conditions they can probably be made to, but I&#x27;ve seen cases where apps that could scale reasonably well to 32 cores on a bare-metal OS having difficulty go beyond 4 cores when inside hardware virtualisation; the hypervisor was migrating threads between cores, which the guest OS was unaware of.<p>My own experience with KVM has been that performance is problematic, thus I don&#x27;t really find it compelling evidence that M:N schedulers can work well. Maybe other hypervisors can do it better, but I don&#x27;t see how they could get around fundamental realities: there usually are more hypervisor threads than real cores available to service them, yet guest OS&#x27;s aren&#x27;t designed to gracefully handle virtual cores unexpectedly freezing for periods of time.