From: Gleb Natapov <gleb@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: kvm <kvm@vger.kernel.org>
Subject: Re: Suggestions for testing VAPIC / TPR patching
Date: Thu, 19 Jan 2012 11:27:58 +0200 [thread overview]
Message-ID: <20120119092758.GH9571@redhat.com> (raw)
In-Reply-To: <4F17DF0D.7020308@siemens.com>
On Thu, Jan 19, 2012 at 10:14:53AM +0100, Jan Kiszka wrote:
> On 2012-01-19 10:02, Gleb Natapov wrote:
> > On Thu, Jan 19, 2012 at 09:35:47AM +0100, Jan Kiszka wrote:
> >> Hi again,
> >>
> >> what is the best way to check if the TPR patching feature of qemu-kvm is
> >> working and performs efficiently? I suppose Windows XP guests, e.g.? How
> >> to measure this best? I'm about to start porting it to upstream and like
> >> to prepare a good test case.
> >>
> > Run WindowsXP on AMD HW without vapic and see number of TPR access exits.
> > Than run it with vapic and check again. Don't forget to check that
> > reboot et al work.
>
> So is this an optimization only for AMD CPUs or can it be reproduced on
> Intel as well? Any CPU feature dependencies?
>
It can be reproduced on Intel as well, but older once. There is
flexpriority module option that you can disable on loading, but I think
it is not enough and you also need to disable tpr_shadow, but there is
not option for that.
--
Gleb.
prev parent reply other threads:[~2012-01-19 9:28 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-19 8:35 Suggestions for testing VAPIC / TPR patching Jan Kiszka
2012-01-19 9:02 ` Gleb Natapov
2012-01-19 9:14 ` Jan Kiszka
2012-01-19 9:27 ` Gleb Natapov [this message]
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