From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adam Greenblatt Subject: Regression in vga performance between 0.11.1 and 0.12.1.1 Date: Wed, 28 Apr 2010 09:33:24 -1000 Message-ID: <4BD88D84.4050601@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org Return-path: Received: from mail-wy0-f174.google.com ([74.125.82.174]:53860 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756839Ab0D1Tdd (ORCPT ); Wed, 28 Apr 2010 15:33:33 -0400 Received: by wye20 with SMTP id 20so1059940wye.19 for ; Wed, 28 Apr 2010 12:33:31 -0700 (PDT) Sender: kvm-owner@vger.kernel.org List-ID: 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. Here's the information you request when submitting a bug report: * what cpu model (examples: Intel Core Duo, Intel Core 2 Duo, AMD Opteron 2210) The host has two Xeon X5650 cpus. * what kvm version you are using. If you're using git directly, provide the output of 'git describe'. I'm using the kvm included with the stock 2.6.32.12 kernel, and two different qemu-kvms: version 0.11.1, which works fine, and version 0.12.1.1, which has the regression. * the host kernel version I'm running kernel 2.6.32.12 on the host. * what host kernel arch you are using (i386 or x86_64) i386. * what guest you are using, including OS type (Linux, Windows, Solaris, etc.), bitness (32 or 64), kernel version Guests that are affected: Ubuntu 9.04 - kernel 2.6.28-18, 32 bits Ubuntu 9.10 - kernel 2.6.31-20, 32 bits Ubuntu 10.04 - kernel 2.6.32-21, 32-bits Guests that aren't affected: Windows XP SP3, Windows Vista SP2: both 32 bits * the qemu command line you are using to start the guest Here's one that works: DISPLAY=:0.2 ~/qemu0111/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-9.10/0006.img Here's one that works, but has drastically slower graphics (the only change is which qemu-system-x86_64 I'm running.) DISPLAY=:0.2 ~/qemu01211/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-9.10/0006.img Here are two that work fine with either binary: DISPLAY=:0.2 ~/qemu01211/bin/qemu-system-x86_64 -m 1536 -soundhw es1370 -usb -usbdevice tablet -localtime -vga std -cpu core2duo -snapshot -name "VXP (r/o)",process="VXP" -net nic,macaddr=DE:AD:BE:EF:00:01 -net tap,vlan=0,ifname=tap0,script=no,downscript=no /vm/xp/0024.img DISPLAY=:0.2 ~/qemu01211/bin/qemu-system-x86_64 -m 1536 -soundhw es1370 -smp 2 -usb -usbdevice tablet -localtime -vga std -cpu core2duo -snapshot -name "VVista (r/o)",process="VVista" -net nic,macaddr=DE:AD:BE:EF:00:02 -net tap,vlan=0,ifname=tap1,script=no,downscript=no /vm/vista/0009.img * whether the problem goes away if using the -no-kvm-irqchip or -no-kvm-pit switch. Neither of these switches change the results. * whether the problem also appears with the -no-kvm switch. This switch makes everything run so much slower that I can't tell if it changes the results. Please cc me if you have any questions, as I'm not subscribed to the kvm list. Thanks for working on kvm, it's a great piece of software! Aloha, Adam Greenblatt