From: Paolo Bonzini <pbonzini@redhat.com>
To: "Durrant, Paul" <pdurrant@amazon.co.uk>,
Peter Zijlstra <peterz@infradead.org>,
"Allister, Jack" <jalliste@amazon.com>
Cc: "bp@alien8.de" <bp@alien8.de>,
"diapop@amazon.co.uk" <diapop@amazon.co.uk>,
"hpa@zytor.com" <hpa@zytor.com>,
"jmattson@google.com" <jmattson@google.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"metikaya@amazon.co.uk" <metikaya@amazon.co.uk>,
"mingo@redhat.com" <mingo@redhat.com>,
"rkrcmar@redhat.com" <rkrcmar@redhat.com>,
"sean.j.christopherson@intel.com"
<sean.j.christopherson@intel.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"vkuznets@redhat.com" <vkuznets@redhat.com>,
"wanpengli@tencent.com" <wanpengli@tencent.com>,
"x86@kernel.org" <x86@kernel.org>
Subject: Re: ...\n
Date: Tue, 31 May 2022 17:51:47 +0200 [thread overview]
Message-ID: <307f19cc-322e-c900-2894-22bdee1e248a@redhat.com> (raw)
In-Reply-To: <059ab3327ac440479ecfdf49fa054347@EX13D32EUC003.ant.amazon.com>
On 5/31/22 16:52, Durrant, Paul wrote:
>> -----Original Message-----
>> From: Peter Zijlstra <peterz@infradead.org>
>> Sent: 31 May 2022 15:44
>> To: Allister, Jack <jalliste@amazon.com>
>> Cc: bp@alien8.de; diapop@amazon.co.uk; hpa@zytor.com; jmattson@google.com; joro@8bytes.org;
>> kvm@vger.kernel.org; linux-kernel@vger.kernel.org; metikaya@amazon.co.uk; mingo@redhat.com;
>> pbonzini@redhat.com; rkrcmar@redhat.com; sean.j.christopherson@intel.com; tglx@linutronix.de;
>> vkuznets@redhat.com; wanpengli@tencent.com; x86@kernel.org
>> Subject: RE: [EXTERNAL]...\n
>>
>>
>> On Tue, May 31, 2022 at 02:02:36PM +0000, Jack Allister wrote:
>>> The reasoning behind this is that you may want to run a guest at a
>>> lower CPU frequency for the purposes of trying to match performance
>>> parity between a host of an older CPU type to a newer faster one.
>>
>> That's quite ludicrus. Also, then it should be the host enforcing the
>> cpufreq, not the guest.
>
> I'll bite... What's ludicrous about wanting to run a guest at a lower CPU freq to minimize observable change in whatever workload it is running?
Well, the right API is cpufreq, there's no need to make it a KVM
functionality.
Paolo
next prev parent reply other threads:[~2022-05-31 15:51 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-31 10:59 [PATCH] KVM: VMX: CPU frequency scaling for intel x86_64 KVM guests Jack Allister
2022-05-31 11:43 ` Metin Kaya
2022-05-31 18:11 ` Paolo Bonzini
2022-06-01 12:55 ` David Woodhouse
2022-05-31 13:38 ` Peter Zijlstra
2022-05-31 14:02 ` ...\n Jack Allister
2022-05-31 14:44 ` ...\n Peter Zijlstra
2022-05-31 14:52 ` ...\n Durrant, Paul
2022-05-31 15:51 ` Paolo Bonzini [this message]
2022-06-01 7:57 ` ...\n Vitaly Kuznetsov
2022-06-01 8:59 ` ...\n Paolo Bonzini
2022-06-01 10:19 ` ...\n Peter Zijlstra
2022-06-01 6:52 ` ...\n Peter Zijlstra
2022-06-01 8:03 ` ...\n Vitaly Kuznetsov
2022-06-01 8:25 ` ...\n Christophe de Dinechin
2022-06-01 8:54 ` ...\n Durrant, Paul
2022-06-01 8:57 ` ...\n Paolo Bonzini
2022-06-01 9:20 ` ...\n Durrant, Paul
2022-06-01 9:43 ` ...\n Amit Shah
2022-06-01 13:14 ` ...\n David Woodhouse
2022-05-31 14:52 ` ...\n Paolo Bonzini
2022-05-31 15:27 ` ...\n Peter Zijlstra
2022-05-31 15:01 ` [PATCH] KVM: VMX: CPU frequency scaling for intel x86_64 KVM guests Vitaly Kuznetsov
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