Re: [PATCH v4 0/3] KVM: Yield to IPI target if necessary

From: Paolo Bonzini
Date: Tue Jul 02 2019 - 12:49:07 EST


On 11/06/19 14:23, Wanpeng Li wrote:
> The idea is from Xen, when sending a call-function IPI-many to vCPUs,
> yield if any of the IPI target vCPUs was preempted. 17% performance
> increasement 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).
>
> v3 -> v4:
> * check map->phys_map[dest_id]
> * more cleaner kvm_sched_yield()
>
> v2 -> v3:
> * add bounds-check on dest_id
>
> v1 -> v2:
> * check map is not NULL
> * check map->phys_map[dest_id] is not NULL
> * make kvm_sched_yield static
> * change dest_id to unsinged long
>
> Wanpeng Li (3):
> KVM: X86: Yield to IPI target if necessary
> KVM: X86: Implement PV sched yield hypercall
> KVM: X86: Expose PV_SCHED_YIELD CPUID feature bit to guest
>
> Documentation/virtual/kvm/cpuid.txt | 4 ++++
> Documentation/virtual/kvm/hypercalls.txt | 11 +++++++++++
> arch/x86/include/uapi/asm/kvm_para.h | 1 +
> arch/x86/kernel/kvm.c | 21 +++++++++++++++++++++
> arch/x86/kvm/cpuid.c | 3 ++-
> arch/x86/kvm/x86.c | 21 +++++++++++++++++++++
> include/uapi/linux/kvm_para.h | 1 +
> 7 files changed, 61 insertions(+), 1 deletion(-)
>

Queued, thanks.

Paolo