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From: Paolo Bonzini <pbonzini@redhat.com>
To: Jim Mattson <jmattson@google.com>, "Li,Rongqing" <lirongqing@baidu.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	kvm list <kvm@vger.kernel.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	"H . Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@alien8.de>,
	Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Joerg Roedel <joro@8bytes.org>,
	Wanpeng Li <wanpengli@tencent.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>
Subject: Re: [PATCH] [RFC] kvm: x86: emulate APERF/MPERF registers
Date: Mon, 27 Apr 2020 21:10:26 +0200	[thread overview]
Message-ID: <f3c2cc31-6388-f7b5-48fd-fb19d059eea3@redhat.com> (raw)
In-Reply-To: <CALMp9eQrGuqzy_ZRu+qU3A7PRkoi8JHWFRpm---cMhp9+J4j8A@mail.gmail.com>

On 27/04/20 19:30, Jim Mattson wrote:
>>>> I would like to see performance data before enabling this
>>>> unconditionally.
>>> I wouldn't want this to be enabled unconditionally anyway,
>>> because you need to take into account live migration to and from
>>> processors that do not have APERF/MPERF support.
>>> 
>>> Paolo
>> I will add a kvm parameter to consider whether enable MPERF/APERF
>> emulations, and make default value to false
>
> Wouldn't it be better to add a per-VM capability to enable this
> feature?

Yes, you it would be better to use KVM_ENABLE_CAP indeed.

Paolo


  reply	other threads:[~2020-04-27 19:10 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-24  5:08 [PATCH] [RFC] kvm: x86: emulate APERF/MPERF registers Li RongQing
2020-04-24 10:01 ` Peter Zijlstra
2020-04-24 14:46   ` Sean Christopherson
2020-04-24 16:25     ` Jim Mattson
2020-04-24 16:30       ` Paolo Bonzini
2020-04-26  3:24         ` 答复: " Li,Rongqing
2020-04-27 17:30           ` Jim Mattson
2020-04-27 19:10             ` Paolo Bonzini [this message]
2020-04-26  3:22     ` 答复: " Li,Rongqing
2020-04-26  8:30   ` Li,Rongqing

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