From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 00/10] in-kernel APIC v3 (kernel side) Date: Mon, 14 May 2007 15:14:43 +0300 Message-ID: <464852B3.3050306@qumranet.com> References: <20070510123831.10200.4769.stgit@novell1.haskins.net> <64F9B87B6B770947A9F8391472E032160BBA66AF@ehost011-8.exch011.intermedia.net> <4642E39D.BA47.005A.0@novell.com><4642E39D.BA47.005A.0@novell.com> <464706BF.6000808@qumranet.com> <464816AB.BA47.005A.0@novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Gregory Haskins Return-path: In-Reply-To: <464816AB.BA47.005A.0-Et1tbQHTxzrQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Gregory Haskins wrote: >> A good test is to let Windows boot and idle itself, then compare the >> process cpu time under the TIME+ column with model- 0 and model- 1. >> > > Will do. One that that I notice that I can't explain yet is as follows: > > When I boot windows + level-1, the point at which windows is running in 16 bit real-mode in the very beginning (before the splashscreen comes up), we seem to take a very large number of exits for instruction emulation. This ends up being a little storm of activity for about 1 second or so. I am not really sure why this happens with the new code and not with the old. It doesnt seem to hurt anything other than extra CPU used. But its weird nonetheless. > > Very strange. Maybe it is a problem with emulating the apic disabled mode. Or maybe the initial state of the apic is different between qemu and kvm+apic. >> Since the vast majority of exits in the scenario are hitting the tpr, >> I'd be unsurprised if the time if 50% lower or so. >> > > Yeah, the new code essentially converts all those TPR exits to lightweight. Nothing more, nothing less. I could be crazy, but my perception is the GUI is *much* more responsive because of it, however. Windows draw very fast and it actually seems usable. Whereas trunk+ACPI always feels sluggish. I don't know of a good benchmark to run to see if there really is an improvement, however. > Just the cpu time spent during boot would be a good indication. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/