From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adam Greenblatt Subject: Re: Regression in vga performance between 0.11.1 and 0.12.1.1 Date: Sat, 01 May 2010 09:17:34 -1000 Message-ID: <4BDC7E4E.30102@gmail.com> References: <4BD88D84.4050601@gmail.com> <4BDA87A8.3020503@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mail-px0-f174.google.com ([209.85.212.174]:33199 "EHLO mail-px0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753828Ab0EATRh (ORCPT ); Sat, 1 May 2010 15:17:37 -0400 Received: by pxi17 with SMTP id 17so686304pxi.19 for ; Sat, 01 May 2010 12:17:37 -0700 (PDT) In-Reply-To: <4BDA87A8.3020503@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi, Sure -- you can download a tarball of kvm_stat logfiles from: http://misc.cyclecounters.org/qemu-logs.tgz I ran three workloads (a short, medium, and long) against both 0.11.1 and 0.12.3. Each workload was started with: time ~/qemu-0.12.3/bin/qemu-system-x86_64 -m 1536 -soundhw es1370 -smp 4 -usb -usbdevice tablet -vga std -cpu core2duo -snapshot -name "VKoala (r/o)",process="VKoala" -net nic,macaddr=DE:AD:BE:EF:00:08 -net tap,vlan=0,ifname=tap6,script=no,downscript=no /vm/ubuntu-9.10/0008.img (or ~/qemu-0.11.1/bin/... and the same options.) For the "short" workload, I just shut down the Ubuntu guest immediately after it finishes logging me in. For the "medium" workload, I open up an 80x43 terminal window in the guest, and execute: yes 1234567890123456789012345678901234567890 | head -n 10000 before shutting down the guest. For the "long" workload, I open up the same terminal window and execute: yes 1234567890123456789012345678901234567890 | head -n 100000 before shutting down the guest. When running these workloads under 0.12.3, you can watch the screen redraw; it takes 1 or 2 seconds just to put up the desktop background after the splash screen. Top shows the `VKoala' process as pegging one or more cpus, while the host's X server is essentially idle (< 5% of a cpu). When running these workloads under 0.11.1, the screen redraw is too fast to notice -- it appears to just "blink" up instantly. Top shows the `VKoala' process as pegging one or more cpus during boot. When the terminal is busy, top shows `VKoala' and the host's X server both using ~60% of a cpu -- so the guest is probably being somewhat limited by the host's wimpy graphics. Hope this is the info you needed. Thanks for your help! Aloha, Adam Avi Kivity wrote: > On 04/28/2010 10:33 PM, Adam Greenblatt wrote: >> Hi, >> I noticed that certain guests (for example, Ubuntu 9.04, Ubuntu 9.10, >> and the Ubuntu 10.04 release candidate) show dramatically (~100x) slower >> graphical output when running under qemu-kvm-0.12.1.1 than under >> qemu-kvm-0.11.1. >> Other guests, notably Windows XP and Windows Vista, run fine under both >> version of qemu. The regression is still present in qemu-kvm-0.12.3. > > > Please post kvm_stat output for the fast and slow cases (preferably > running the same workload, perhaps a web page displaying an animation). >