From: Avi Kivity <avi@redhat.com>
To: Jes Sorensen <Jes.Sorensen@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>, Joerg Roedel <joro@8bytes.org>,
KVM General <kvm@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Zachary Amsden <zamsden@redhat.com>,
Gleb Natapov <gleb@redhat.com>,
ming.m.lin@intel.com, "Zhang,
Yanmin" <yanmin_zhang@linux.intel.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Arjan van de Ven <arjan@infradead.org>,
Fr??d??ric Weisbecker <fweisbec@gmail.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>
Subject: Re: KVM PMU virtualization
Date: Fri, 26 Feb 2010 15:55:54 +0200 [thread overview]
Message-ID: <4B87D2EA.1090503@redhat.com> (raw)
In-Reply-To: <4B87CE93.1070906@redhat.com>
On 02/26/2010 03:37 PM, Jes Sorensen wrote:
> On 02/26/10 14:31, Ingo Molnar wrote:
>> You are missing two big things wrt. compatibility here:
>>
>> 1) The first upgrade overhead a one time overhead only.
>>
>> 2) Once a Linux guest has upgraded, it will work in the future,
>> with _any_
>> future CPU - _without_ having to upgrade the guest!
>>
>> Dont you see the advantage of that? You can instrument an old system
>> on new
>> hardware, without having to upgrade that guest for the new CPU support.
>
> That would only work if you are guaranteed to be able to emulate old
> hardware on new hardware. Not going to be feasible, so then we are in a
> real mess.
>
That actually works on the Intel-only architectural pmu. I'm beginning
to like it more and more.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
next prev parent reply other threads:[~2010-02-26 13:56 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-25 15:04 KVM PMU virtualization Jes Sorensen
2010-02-25 15:44 ` Jan Kiszka
2010-02-25 16:26 ` Ingo Molnar
2010-02-26 2:52 ` Zhang, Yanmin
2010-02-26 8:45 ` Ingo Molnar
2010-02-26 11:03 ` Jes Sorensen
2010-02-25 17:34 ` Joerg Roedel
2010-02-26 2:55 ` Zhang, Yanmin
2010-02-26 8:51 ` Joerg Roedel
2010-02-26 9:17 ` Ingo Molnar
2010-02-26 10:42 ` Joerg Roedel
2010-02-26 10:56 ` Ingo Molnar
2010-03-02 7:09 ` Zhang, Yanmin
2010-03-02 9:36 ` Ingo Molnar
2010-03-03 3:32 ` Zhang, Yanmin
2010-03-03 9:27 ` Zhang, Yanmin
2010-03-03 10:13 ` Peter Zijlstra
2010-03-04 0:52 ` Zhang, Yanmin
2010-03-03 10:15 ` Peter Zijlstra
2010-03-04 1:00 ` Zhang, Yanmin
2010-03-10 9:29 ` Zhang, Yanmin
2010-03-02 9:57 ` Peter Zijlstra
2010-02-26 8:42 ` Ingo Molnar
2010-02-26 9:46 ` Avi Kivity
2010-02-26 10:39 ` Joerg Roedel
2010-02-26 10:46 ` Ingo Molnar
2010-02-26 10:51 ` Avi Kivity
2010-02-26 11:06 ` Joerg Roedel
2010-02-26 11:18 ` Jes Sorensen
2010-02-26 11:24 ` Ingo Molnar
2010-02-26 11:25 ` Jes Sorensen
2010-02-26 11:20 ` Ingo Molnar
2010-02-26 10:44 ` Ingo Molnar
2010-02-26 11:16 ` Avi Kivity
2010-02-26 11:26 ` Ingo Molnar
2010-02-26 11:47 ` Avi Kivity
2010-02-26 11:23 ` Jes Sorensen
2010-02-26 11:42 ` Ingo Molnar
2010-02-26 11:51 ` Avi Kivity
2010-02-26 12:07 ` Ingo Molnar
2010-02-26 12:20 ` Avi Kivity
2010-02-26 12:38 ` Ingo Molnar
2010-02-26 13:04 ` Avi Kivity
2010-02-26 13:13 ` Jes Sorensen
2010-02-26 13:27 ` Ingo Molnar
2010-02-26 13:33 ` Avi Kivity
2010-02-26 14:07 ` Jes Sorensen
2010-02-26 14:11 ` Avi Kivity
2010-02-26 13:18 ` Ingo Molnar
2010-02-26 13:34 ` Jes Sorensen
2010-02-26 12:56 ` Jes Sorensen
2010-02-26 13:31 ` Ingo Molnar
2010-02-26 13:37 ` Jes Sorensen
2010-02-26 13:55 ` Avi Kivity [this message]
2010-02-26 14:27 ` Peter Zijlstra
2010-02-26 14:54 ` Avi Kivity
2010-02-26 15:08 ` Peter Zijlstra
2010-02-26 15:11 ` Avi Kivity
2010-02-26 15:18 ` Peter Zijlstra
2010-02-26 15:55 ` Peter Zijlstra
2010-02-26 16:06 ` Avi Kivity
2010-03-01 19:03 ` Zachary Amsden
2010-03-01 18:54 ` Zachary Amsden
2010-02-26 13:40 ` Avi Kivity
2010-02-26 14:01 ` Ingo Molnar
2010-02-26 14:22 ` Avi Kivity
2010-02-26 14:37 ` Ingo Molnar
2010-02-26 16:03 ` Avi Kivity
2010-02-26 16:07 ` Avi Kivity
2010-02-26 13:28 ` Peter Zijlstra
2010-02-26 13:44 ` Avi Kivity
2010-02-26 13:51 ` Jes Sorensen
2010-02-26 14:42 ` Peter Zijlstra
2010-03-08 18:14 ` Avi Kivity
2010-02-26 12:49 ` Jes Sorensen
2010-02-26 13:06 ` Ingo Molnar
2010-02-26 13:30 ` Avi Kivity
2010-02-26 13:32 ` Jes Sorensen
2010-02-26 13:44 ` Ingo Molnar
2010-02-26 13:53 ` Avi Kivity
2010-02-26 14:12 ` Ingo Molnar
2010-02-26 14:53 ` Avi Kivity
2010-02-26 15:14 ` Peter Zijlstra
2010-02-28 16:34 ` Joerg Roedel
2010-02-28 16:31 ` Joerg Roedel
2010-02-28 16:11 ` Joerg Roedel
2010-03-01 8:39 ` Ingo Molnar
2010-03-01 8:58 ` Joerg Roedel
2010-03-01 9:04 ` Ingo Molnar
2010-03-01 8:44 ` Ingo Molnar
2010-03-01 11:11 ` Joerg Roedel
2010-03-01 17:17 ` Peter Zijlstra
2010-03-01 18:36 ` Joerg Roedel
2010-03-08 10:15 ` Avi Kivity
2010-02-26 14:49 ` Peter Zijlstra
2010-02-26 14:50 ` Peter Zijlstra
2010-02-26 13:31 ` Jes Sorensen
2010-03-01 17:22 ` Zachary Amsden
2010-02-26 11:01 ` Jes Sorensen
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