Re: [PATCH v2 2/3] KVM: X86: Implement PV sched yield hypercall

[Wanpeng Li]

On Tue, 28 May 2019 at 17:12, Christian Borntraeger
<borntraeger@xxxxxxxxxx> wrote:
>
> On 28.05.19 02:53, Wanpeng Li wrote:
> > From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> >
> > The target vCPUs are in runnable state after vcpu_kick and suitable
> > as a yield target. This patch implements the sched yield hypercall.
> >
> > 17% performace increase of ebizzy benchmark can be observed in an
> > over-subscribe environment. (w/ kvm-pv-tlb disabled, testing TLB flush
> > call-function IPI-many since call-function is not easy to be trigged
> > by userspace workload).
> >
> > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> > Cc: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
> > Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
>
> FWIW, we do have a similar interface in s390.
>
> See arch/s390/kvm/diag.c  __diag_time_slice_end_directed for our implementation.

Good to know this. :)

Regards,
Wanpeng Li