I use qemu (with kvm), with the display set to VNC so that I can use the VM from other computers on the LAN. In the past, the performance of display updates was great. But recently, I updated to 0.12.5, and I find that the display updates have become very slow. It's almost unusable. I'm on a gigabit LAN, so the network isn't the problem. I'd report this upstream, but their submission guidelines say not to report problems in distro packages. Reproducible: Always
$ emerge --info Portage 2.1.9.20 (default/linux/amd64/10.0, gcc-4.4.5, glibc-2.12.1-r1, 2.6.35-gentoo-r5 x86_64) ================================================================= System uname: Linux-2.6.35-gentoo-r5-x86_64-Intel-R-_Core-TM-2_Quad_CPU_Q9450_@_2.66GHz-with-gentoo-2.0.1 Timestamp of tree: Wed, 20 Oct 2010 07:00:01 +0000 app-shells/bash: 4.1_p9 dev-java/java-config: 2.1.11 dev-lang/python: 2.6.6-r1, 3.1.2-r4 dev-util/cmake: 2.8.1-r2 sys-apps/baselayout: 2.0.1 sys-apps/openrc: 0.6.3 sys-apps/sandbox: 2.3-r1 sys-devel/autoconf: 2.13, 2.68 sys-devel/automake: 1.8.5-r4, 1.9.6-r3, 1.10.3, 1.11.1 sys-devel/binutils: 2.20.1-r1 sys-devel/gcc: 4.4.5 sys-devel/gcc-config: 1.4.1 sys-devel/libtool: 2.2.10 sys-devel/make: 3.82 virtual/os-headers: 2.6.35 (sys-kernel/linux-headers) ACCEPT_KEYWORDS="amd64 ~amd64" ACCEPT_LICENSE="*" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-O2 -march=core2 -ggdb -pipe" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/share/X11/xkb /usr/share/config" CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/env.d /etc/env.d/java/ /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/php/apache2-php5/ext-active/ /etc/php/cgi-php5/ext-active/ /etc/php/cli-php5/ext-active/ /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo /etc/texmf/language.dat.d /etc/texmf/language.def.d /etc/texmf/updmap.d /etc/texmf/web2c" CXXFLAGS="-O2 -march=core2 -ggdb -pipe" DISTDIR="/usr/portage/distfiles" EMERGE_DEFAULT_OPTS="--jobs=2" FEATURES="assume-digests binpkg-logs distlocks fixlafiles fixpackages news parallel-fetch protect-owned sandbox sfperms splitdebug strict unknown-features-warn unmerge-logs unmerge-orphans userfetch" GENTOO_MIRRORS="http://gentoo.osuosl.org/ http://gentoo.netnitco.net http://mirror.csclub.uwaterloo.ca/gentoo-distfiles/ ftp://mirror.datapipe.net/gentoo ftp://mirror.csclub.uwaterloo.ca/gentoo-distfiles/ http://gentoo.mirrors.easynews.com/linux/gentoo/ ftp://ftp.free.fr/mirrors/ftp.gentoo.org/ ftp://gentoo.imj.fr/pub/gentoo/ ftp://distro.ibiblio.org/pub/linux/distributions/gentoo/" LANG="en_US.utf8" LDFLAGS="-Wl,-O1 -Wl,--as-needed" LINGUAS="en en_US" MAKEOPTS="--jobs=3 --load-average=7" PKGDIR="/usr/portage/packages" PORTAGE_CONFIGROOT="/" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --stats --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="/usr/local/portage" SYNC="rsync://rsync.gentoo.org/gentoo-portage" USE="X a52 aac aalib acl acpi alsa amd64 apache2 aspell autotrace bash-completion berkdb bidi bonjour bzip2 cairo cdda cdio cdr cli composite cracklib crypt ctype cups curl cxx dbus device-mapper dri dts dvd dvdr encode exif extras fbcon ffmpeg fftw filter flac fontconfig fortran freetype gcj gd gdbm git glib gmm gnutls gpm graphviz gs httpd iconv imagemagick ipp ipv6 ithreads jadetex java jpeg jpeg2k kde kde4 kerberos kpathsea kvm lame lapack latex lcms ldap live lm_sensors lzma mad matroska mdnsresponder-compat mjpeg mkl mmx mng modules mp3 mpeg mudflap multilib mysql mysqli ncurses nls nptl nptlonly ogg oggvorbis openexr opengl openmp openssl pam pcre pdf perl php plasma plotutils png ppds pppd python qemu qt3support qt4 quicktime readline rss ruby samba sasl secure-delete semantic-desktop session smp spl sql sse sse2 sse3 ssl stream subversion svg sysfs tcl tcpd theora threads thumbnail tiff tk truetype unicode utempter vcd vlm vnc vorbis webkit wxwindows x264 xcomposite xml xorg xv xvid zeroconf zlib" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mmap_emul mulaw multi null plug rate route share shm softvol" APACHE2_MODULES="actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf superstar2 timing tsip tripmate tnt ubx" INPUT_DEVICES="evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LINGUAS="en en_US" PHP_TARGETS="php-5.2" QEMU_SOFTMMU_TARGETS="i386 x86_64" QEMU_USER_TARGETS="i386 x86_64" RUBY_TARGETS="ruby18 ruby19" USERLAND="GNU" VIDEO_CARDS="radeon" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account" Unset: CPPFLAGS, CTARGET, FFLAGS, INSTALL_MASK, LC_ALL, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS
I think the problem is related to the sheer volume of data it's sending. Dragging a window frame (not contents) should not generate tens of megs per second of data transfer. VNC has protocol command to do things like copy rectangles. It appears that qemu is no longer using that optimization and is just sending all raw pixel updates.
I've done some more digging. In order to get high res modes, I use "-vga std", rather than cirrus. As I understand it, this should use VESA to do acceleration, but that isn't happening correctly.
Interesting. Some googling reveals lots of complaints about this problem. For me, it appears that the recent update has made this slower still.
Timothy, do you still have this issue with the latest version of qemu-kvm in the tree?
I would like to test this, but I cannot. Mouse support is completely unusable. I've always had to use the "-usbdevice tablet" option in order for the mouse pointers to line up, and this doesn't work anymore. I don't know if this is a gentoo-specific regression or what, but now I can't use my VMs at all.
Please test with the latest version in the tree.
