From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: Suggestions for testing VAPIC / TPR patching Date: Thu, 19 Jan 2012 11:27:58 +0200 Message-ID: <20120119092758.GH9571@redhat.com> References: <4F17D5E3.1030105@siemens.com> <20120119090219.GG9571@redhat.com> <4F17DF0D.7020308@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:1207 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756088Ab2ASJ2B (ORCPT ); Thu, 19 Jan 2012 04:28:01 -0500 Content-Disposition: inline In-Reply-To: <4F17DF0D.7020308@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: 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.