Re: [PATCH] sched,kvm: Fix KVM preempt_notifier usage

Peter Zijlstra
2015-07-03T12:19:21Z

On Fri, Jul 03, 2015 at 01:12:11PM +0200, Paolo Bonzini wrote:
> In fact you shouldn't have just tested the patch on a case _without_
> preemption notifiers, you should have also benchmarked the impact that
> static keys have _with_ preemption notifiers. In a
> not-really-artificial case (one single-processor guest running on the
> host), the static key patch adds a static_key_slow_inc on a relatively
> hot path for KVM, which is not acceptable.

Spawning the first vcpu is a hot path?