From: Ingo Molnar <mingo@elte.hu>
To: Avi Kivity <avi@redhat.com>
Cc: Jes Sorensen <Jes.Sorensen@redhat.com>,
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 14:31:49 +0100 [thread overview]
Message-ID: <20100226133149.GA23422@elte.hu> (raw)
In-Reply-To: <4B87BC74.7050207@redhat.com>
* Avi Kivity <avi@redhat.com> wrote:
> Or do you mean to define a new, kvm-specific pmu model and feed it off the
> host pmu? In this case all the guests will need to be taught about it,
> which raises the compatibility problem.
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.
With the 'steal the PMU' messy approach the guest OS has to be upgraded to the
new CPU type all the time. Ad infinitum.
Ingo
next prev parent reply other threads:[~2010-02-26 13:32 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 [this message]
2010-02-26 13:37 ` Jes Sorensen
2010-02-26 13:55 ` Avi Kivity
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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