From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Abrahams Subject: Re: kvm somehow exempt from frequency scaling? Date: Wed, 11 Apr 2007 14:31:39 -0400 Message-ID: <87fy76ahkk.fsf@grogan.peloton> References: <87veg6bck6.fsf@grogan.peloton> <4619EB19.20305@qumranet.com> <87mz1gj1pr.fsf@grogan.peloton> <461B3CBB.3040401@qumranet.com> <461B63E4.3080804@mr511.de> <87hcrnciom.fsf@grogan.peloton> <87fy76c1el.fsf@grogan.peloton> <461D1D3F.8050001@mr511.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Michael Riepe Return-path: In-Reply-To: <461D1D3F.8050001-0QoEqw4nQxo@public.gmane.org> (Michael Riepe's message of "Wed\, 11 Apr 2007 19\:39\:11 +0200") 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 on Wed Apr 11 2007, Michael Riepe wrote: > Hi! > > David Abrahams wrote: > [...] >>>More data: it definitely seems to make a difference whether the VM's >>>desktop is showing. If I switch Gnome workspaces so it's not visible, >>>it doesn't seem to drive the frequency up. > > Because it doesn't have to redraw the window? > > What happens if you hide the qemu window below another one, e.g. your > favorite web browser? It seems to make progress. I can play internet radio in the VM and I keep hearing it (glitchy, but it doesn't stop). >> In fact, kvm doesn't seem to make any progress at all :(. I'm >> currently going through the "microsoft update" dance on a VM there, >> and I literally left for an hour during which there was no progress >> because the QEMU window wasn't visible. >> >> Even stranger, if I minimize the QEMU window and then switch >> workspaces, it gets plenty of cycles. > > I guess that's a qemu and/or SDL issue. SDL? > Ideally, the screen should only be updated when the window is mapped > (via XMapWindow) *and* visible (that is, neither fully obscured nor > moved outside the visible part of the screen). Since "fully obscured" is > hard to test for, this usually translates to "mapped and not off-screen". Yeah, but I don't care about the window being updated. I want the virtual CPU to make progress. Switching workspaces is literally like suspending the VM! > When a window is minimized ("iconified"), it usually is unmapped and > another one (the "icon window") is mapped instead. When switching > workspaces, however, some window managers just move the window away (say > to x=10000,y=10000) but keep it mapped. If there is no test for > visibility (or if the test doesn't work correctly), SDL may happily > continue updating the window's contents - and that will burn a lot of > cycles. > > IMO, there's a lot of room for improvement here. But it has nothing to > do with kvm in the first place (unless you consider qemu an integral > part of kvm, which I don't). I don't either, but it's not 100% clear to me yet that this is a qemu problem. Maybe I'll report it in a QEMU forum as well. -- Dave Abrahams Boost Consulting http://www.boost-consulting.com Don't Miss BoostCon 2007! ==> http://www.boostcon.com ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV