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From:   Wanpeng Li <kernellwp@gmail.com>
Date:   Tue, 18 Jun 2019 17:00:36 +0800
Message-ID: <CANRm+CwfXViF34eLma5ZnqjT96Sq=XehpBiTZTj1TfJnkevVMA@mail.gmail.com>
Subject: Re: [PATCH v4 0/3] KVM: Yield to IPI target if necessary
To:     LKML <linux-kernel@vger.kernel.org>, kvm <kvm@vger.kernel.org>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>
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ping, :)
On Tue, 11 Jun 2019 at 20:23, Wanpeng Li <kernellwp@gmail.com> 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(-)
>
> --
> 2.7.4
>