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Re: [PATCH v2 0/4] KVM: optimize the kvm_vcpu_on_spin

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On 2017/8/8 15:41, Cornelia Huck wrote:

> On Tue, 8 Aug 2017 12:05:31 +0800
> "Longpeng(Mike)" <longpeng2@huawei.com> wrote:
> 
>> This is a simple optimization for kvm_vcpu_on_spin, the
>> main idea is described in patch-1's commit msg.
> 
> I think this generally looks good now.
> 
>>
>> I did some tests base on the RFC version, the result shows
>> that it can improves the performance slightly.
> 
> Did you re-run tests on this version?


Hi Cornelia,

I didn't re-run tests on V2. But the major difference between RFC and V2
is that V2 only cache result for X86 (s390/arm needn't) and V2 saves a
expensive operation ( 440-1400 cycles on my test machine ) for X86/VMX.

So I think V2's performance is at least the same as RFC or even slightly
better. :)

> 
> I would also like to see some s390 numbers; unfortunately I only have a
> z/VM environment and any performance numbers would be nearly useless
> there. Maybe somebody within IBM with a better setup can run a quick
> test?
> 
> .
> 


-- 
Regards,
Longpeng(Mike)

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[PATCH v2 0/4] KVM: optimize the kvm_vcpu_on_spin "Longpeng(Mike)" <longpeng2@huawei.com> - 2017-08-08 06:10 +0200
  [PATCH v2 4/4] KVM: arm: implements the kvm_arch_vcpu_in_kernel() "Longpeng(Mike)" <longpeng2@huawei.com> - 2017-08-08 06:10 +0200
    Re: [PATCH v2 4/4] KVM: arm: implements the kvm_arch_vcpu_in_kernel() Christoffer Dall <cdall@linaro.org> - 2017-08-08 09:40 +0200
      Re: [PATCH v2 4/4] KVM: arm: implements the kvm_arch_vcpu_in_kernel() Christoffer Dall <christoffer.dall@linaro.org> - 2017-08-08 09:50 +0200
  Re: [PATCH v2 0/4] KVM: optimize the kvm_vcpu_on_spin Cornelia Huck <cohuck@redhat.com> - 2017-08-08 09:50 +0200
    Re: [PATCH v2 0/4] KVM: optimize the kvm_vcpu_on_spin "Longpeng (Mike)" <longpeng2@huawei.com> - 2017-08-08 10:20 +0200
      Re: [PATCH v2 0/4] KVM: optimize the kvm_vcpu_on_spin Eric Farman <farman@linux.vnet.ibm.com> - 2017-08-10 15:20 +0200
        Re: [PATCH v2 0/4] KVM: optimize the kvm_vcpu_on_spin "Longpeng (Mike)" <longpeng2@huawei.com> - 2017-08-11 03:50 +0200
        Re: [PATCH v2 0/4] KVM: optimize the kvm_vcpu_on_spin Cornelia Huck <cohuck@redhat.com> - 2017-08-11 09:30 +0200
  Re: [PATCH v2 0/4] KVM: optimize the kvm_vcpu_on_spin David Hildenbrand <david@redhat.com> - 2017-08-08 13:30 +0200
    Re: [PATCH v2 0/4] KVM: optimize the kvm_vcpu_on_spin Christoffer Dall <christoffer.dall@linaro.org> - 2017-08-08 13:40 +0200
    Re: [PATCH v2 0/4] KVM: optimize the kvm_vcpu_on_spin "Longpeng (Mike)" <longpeng2@huawei.com> - 2017-08-08 13:50 +0200
      Re: [PATCH v2 0/4] KVM: optimize the kvm_vcpu_on_spin David Hildenbrand <david@redhat.com> - 2017-08-08 14:00 +0200

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