From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Stephen Hemminger" <sthemmin@microsoft.com>,
kvm@vger.kernel.org, "Radim Krčmář" <rkrcmar@redhat.com>,
"Haiyang Zhang" <haiyangz@microsoft.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
"Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>,
"Bandan Das" <bsd@redhat.com>,
"Roman Kagan" <rkagan@virtuozzo.com>,
devel@linuxdriverproject.org,
"Mohammed Gamal" <mmorsy@redhat.com>
Subject: Re: [PATCH RFC 0/7] KVM: nVMX: enlightened VMCS initial implementation
Date: Thu, 21 Dec 2017 16:08:30 +0100 [thread overview]
Message-ID: <87lghww235.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <c5c1357d-c36a-38bf-6148-8ffb89a0290b@redhat.com> (Paolo Bonzini's message of "Thu, 21 Dec 2017 15:32:14 +0100")
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
WARNING: multiple messages have this Message-ID (diff)
From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, x86@kernel.org,
"Radim Krčmář" <rkrcmar@redhat.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
"Haiyang Zhang" <haiyangz@microsoft.com>,
"Stephen Hemminger" <sthemmin@microsoft.com>,
"Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>,
"Mohammed Gamal" <mmorsy@redhat.com>,
"Cathy Avery" <cavery@redhat.com>, "Bandan Das" <bsd@redhat.com>,
"Roman Kagan" <rkagan@virtuozzo.com>,
linux-kernel@vger.kernel.org, devel@linuxdriverproject.org
Subject: Re: [PATCH RFC 0/7] KVM: nVMX: enlightened VMCS initial implementation
Date: Thu, 21 Dec 2017 16:08:30 +0100 [thread overview]
Message-ID: <87lghww235.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <c5c1357d-c36a-38bf-6148-8ffb89a0290b@redhat.com> (Paolo Bonzini's message of "Thu, 21 Dec 2017 15:32:14 +0100")
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
next prev parent reply other threads:[~2017-12-21 15:08 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-18 17:17 [PATCH RFC 0/7] KVM: nVMX: enlightened VMCS initial implementation Vitaly Kuznetsov
2017-12-18 17:17 ` [PATCH RFC 1/7] KVM: x86: rename HV_X64_MSR_APIC_ASSIST_PAGE to HV_X64_MSR_VP_ASSIST_PAGE Vitaly Kuznetsov
2017-12-18 17:17 ` Vitaly Kuznetsov
2017-12-18 17:17 ` [PATCH RFC 2/7] KVM: nVMX: modify vmcs12 fields to match Hyper-V enlightened VMCS Vitaly Kuznetsov
2017-12-18 17:17 ` Vitaly Kuznetsov
2017-12-18 20:23 ` Jim Mattson
2017-12-18 20:23 ` Jim Mattson
2017-12-18 21:28 ` Jim Mattson
2017-12-18 21:28 ` Jim Mattson
2017-12-19 12:25 ` Vitaly Kuznetsov
2017-12-19 12:25 ` Vitaly Kuznetsov
2017-12-19 12:37 ` Paolo Bonzini
2017-12-19 12:37 ` Paolo Bonzini
2017-12-19 17:40 ` Jim Mattson
2017-12-19 17:40 ` Jim Mattson
2017-12-19 21:19 ` Paolo Bonzini
2017-12-21 13:02 ` Vitaly Kuznetsov
2017-12-21 13:02 ` Vitaly Kuznetsov
2017-12-19 17:44 ` Jim Mattson
2017-12-19 17:44 ` Jim Mattson
2017-12-18 17:17 ` [PATCH RFC 3/7] KVM: nVMX: add I/O exit ECX, ESI, EDI, EIP vmcs12 fields Vitaly Kuznetsov
2017-12-18 17:17 ` Vitaly Kuznetsov
2017-12-18 17:17 ` [PATCH RFC 4/7] KVM: hyperv: define VP assist page structure and add helpers Vitaly Kuznetsov
2017-12-18 17:17 ` Vitaly Kuznetsov
2017-12-18 17:17 ` [PATCH RFC 5/7] KVM: nVMX: add KVM_CAP_HYPERV_ENLIGHTENED_VMCS capability Vitaly Kuznetsov
2017-12-18 17:17 ` Vitaly Kuznetsov
2017-12-18 17:17 ` [PATCH RFC 6/7] KVM: nVMX: add enlightened VMCS state Vitaly Kuznetsov
2017-12-18 17:17 ` Vitaly Kuznetsov
2017-12-18 17:17 ` [PATCH RFC 7/7] KVM: nVMX: implement enlightened VMPTRLD Vitaly Kuznetsov
2017-12-18 17:17 ` Vitaly Kuznetsov
2017-12-19 12:41 ` [PATCH RFC 0/7] KVM: nVMX: enlightened VMCS initial implementation Paolo Bonzini
2017-12-19 12:41 ` Paolo Bonzini
2017-12-19 13:21 ` Vitaly Kuznetsov
2017-12-21 12:50 ` Vitaly Kuznetsov
2017-12-21 14:32 ` Paolo Bonzini
2017-12-21 14:32 ` Paolo Bonzini
2017-12-21 15:08 ` Vitaly Kuznetsov [this message]
2017-12-21 15:08 ` Vitaly Kuznetsov
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