Messages in this thread |  | | From | Vitaly Kuznetsov <> | Subject | Re: [PATCH RFC 0/7] KVM: nVMX: enlightened VMCS initial implementation | Date | Thu, 21 Dec 2017 16:08:30 +0100 |
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Paolo Bonzini <pbonzini@redhat.com> writes:
> On 21/12/2017 13:50, Vitaly Kuznetsov wrote: >> I'm back with (somewhat frustrating) results (E5-2603): > > v4 (that would be Broadwell)? >
Sorry, v3, actually. Haswell. (the first one supporting vmcs shadowing afaiu).
>> 1) Windows on Hyper-V (no nesting): 1350 cycles >> >> 2) Windows on Hyper-V on Hyper-V: 8600 >> >> 3) Windows on KVM (no nesting): 1150 cycles >> >> 4) Windows on Hyper-V on KVM (no enlightened VMCS): 18200 >> >> 5) Windows on Hyper-V on KVM (enlightened VMCS): 17100 > > What version were you using for KVM? There are quite a few nested virt > optimizations in kvm/queue (which may make enlightened VMCS both more or > less efficient).
This is kvm/queue and I rebased enlightened VMCS patches to it.
> > In particular, with latest kvm/queue you could try tracing vmread and > vmwrite vmexits, and see if you get any. If you do, that might be an > easy few hundred cycles savings.
Will do.
-- Vitaly
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