[Qemu-devel] Re: [PATCH] qemu-kvm: response to SIGUSR1 to start/stop a VCPU (v2)

[Chris Wright]

* Peter Zijlstra (address@hidden) wrote:
> On Wed, 2010-12-01 at 09:17 -0800, Chris Wright wrote:
> > Directed yield and fairness don't mix well either. You can end up
> > feeding the other tasks more time than you'll ever get back.
> 
> If the directed yield is always to another task in your cgroup then
> inter-guest scheduling fairness should be maintained. 
> 
> Yes, but not the inter-vcpu fairness.

That same vcpu doesn't get fair scheduling if it spends its entire
timeslice spinning on a lock held by a de-scheduled vcpu.