From: Gleb Natapov <gleb@redhat.com>
To: "Benoît Canet" <benoit.canet@irqsave.net>
Cc: qemu-devel@nongnu.org, pbonzini@redhat.com,
"Eduardo Habkost" <ehabkost@redhat.com>,
"Andreas Färber" <afaerber@suse.de>,
"Igor Mammedov" <imammedo@redhat.com>
Subject: Re: [Qemu-devel] KVM guest cpu L3 cache and cpufreq
Date: Tue, 27 Aug 2013 16:39:54 +0300 [thread overview]
Message-ID: <20130827133953.GA29736@redhat.com> (raw)
In-Reply-To: <20130827133533.GB5436@irqsave.net>
On Tue, Aug 27, 2013 at 03:35:33PM +0200, Benoît Canet wrote:
> > > > If I understand correctly changing the CPUID L3 cache infos in QEMU will change
> > > > the value displayed in the guest /proc/cpuinfo but will not change the size of
> > > > the l3 cache used by the hardware. So I am chasing a cosmetic bug.
> > > > If it right ?
> > > >
> > > Right.
> > >
> > Well, actually not entirely. An application can query cache sizes and
> > adjust its algorithms accordingly in which case performance can be
> > suboptimal if information in a guest is not accurate.
>
> So maybe what is missing is a CPUID passthrough mode triggered when -cpu host
> is used ?
>
That is missing too, but it should not be default with other CPU models.
--
Gleb.
next prev parent reply other threads:[~2013-08-27 13:40 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-13 18:17 [Qemu-devel] KVM guest cpu L3 cache and cpufreq Benoît Canet
2013-08-26 12:40 ` Gleb Natapov
2013-08-26 12:49 ` Benoît Canet
2013-08-26 14:33 ` Gleb Natapov
2013-08-26 16:45 ` Benoît Canet
2013-08-26 20:47 ` Eduardo Habkost
2013-08-27 13:18 ` Benoît Canet
2013-08-27 13:17 ` Gleb Natapov
2013-08-27 13:20 ` Gleb Natapov
2013-08-27 13:35 ` Benoît Canet
2013-08-27 13:39 ` Gleb Natapov [this message]
2013-08-27 13:37 ` Eduardo Habkost
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