Canvas update in GIMP 2.8.0 is (most of the time) very slow with nvidia-drivers. Ocasionally it gets better. It is way more smooth with nouveau. I use rectangle select tool as a test and it lags a lot. Other tools are slow, too. Menus, when overlapping the canvas, are slow, too. I have i5-2400 CPU, GeForce GT 520 card and 16G of RAM. nvidia-drivers 295.40. Reproducible: Always Steps to Reproduce: 1. Launch GIMP. 2. Create a 800x600 image. 3. Try selecting rectangle areas. Portage 2.2.0_alpha101 (default/linux/amd64/10.0/desktop/kde, gcc-4.5.3, glibc-2.15-r1, 3.3.4-gentoomelf x86_64) ================================================================= System uname: Linux-3.3.4-gentoomelf-x86_64-Intel-R-_Core-TM-_i5-2400_CPU_@_3.10GHz-with-gentoo-2.1 Timestamp of tree: Fri, 04 May 2012 21:45:01 +0000 app-shells/bash: 4.2_p28 dev-java/java-config: 2.1.11-r3 dev-lang/python: 2.7.3-r2, 3.2.3-r1 dev-util/cmake: 2.8.8-r1 dev-util/pkgconfig: 0.26 sys-apps/baselayout: 2.1 sys-apps/openrc: 0.9.9.3 sys-apps/sandbox: 2.5 sys-devel/autoconf: 2.13, 2.69 sys-devel/automake: 1.9.6-r3, 1.11.5 sys-devel/binutils: 2.22-r1 sys-devel/gcc: 4.5.3-r2 sys-devel/gcc-config: 1.7 sys-devel/libtool: 2.4.2 sys-devel/make: 3.82-r3 sys-kernel/linux-headers: 3.3 (virtual/os-headers) sys-libs/glibc: 2.15-r1 Repositories: gentoo Installed sets: @kde, @vim ACCEPT_KEYWORDS="amd64 ~amd64" ACCEPT_LICENSE="* -@EULA PUEL skype-eula AdobeFlash-10.3 Oracle-BCLA-JavaSE" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-O2 -pipe -march=native -mtune=native" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/share/config /usr/share/gnupg/qualified.txt" CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/env.d /etc/env.d/java/ /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo" CXXFLAGS="-O2 -pipe -march=native -mtune=native" DISTDIR="/usr/portage/distfiles" FEATURES="assume-digests binpkg-logs distlocks ebuild-locks fixlafiles news parallel-fetch preserve-libs protect-owned sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch" FFLAGS="" GENTOO_MIRRORS="http://gentoo.bloodhost.ru/ http://mirror.yandex.ru/gentoo-distfiles/ http://trumpetti.atm.tut.fi/gentoo/" LANG="ru_RU.utf8" LDFLAGS="-Wl,-O1 -Wl,--as-needed" LINGUAS="en en_GB ru ja" MAKEOPTS="-j5" PKGDIR="/usr/portage/packages" PORTAGE_CONFIGROOT="/" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --stats --human-readable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="" SYNC="rsync://gentoo.bloodhost.ru/gentoo-portage/" USE="X a52 aac acl acpi alsa amd64 anthy bash-completion bluetooth branding bzip2 cairo cdda cdr cjk cli consolekit cracklib crypt cups cxx dbus declarative directfb djvu dri dts dvd dvdr emboss encode exif fam fbcon ffmpeg firefox flac fortran gdbm gdu gif glitz gpm gstreamer gtk iconv idn immqt-bc ipv6 jpeg kde kipi lame lcms libcaca libnotify lm_sensors m17n-lib mad matroska mmx mng modules mp3 mp4 mpeg mplayer mudflap multilib ncurses nls nptl nptlonly ogg opengl openmp pam pango pcre pdf perl phonon plasma png policykit ppds pppd python qt3support qt4 raw readline sdl semantic-desktop session spell sse sse2 ssl startup-notification svg sysfs tcpd tiff truetype udev unicode usb vdpau vorbis wxwidgets x264 xcb xcomposite xinerama xml xorg xscreensaver xulrunner xv xvid 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" CALLIGRA_FEATURES="kexi words flow plan sheets stage tables krita karbon braindump" CAMERAS="ptp2" 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" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" LINGUAS="en en_GB ru ja" NGINX_MODULES_HTTP="access auth_basic autoindex browser charset empty_gif fastcgi geo gzip limit_req limit_zone map memcached proxy referer rewrite scgi split_clients ssi upstream_ip_hash userid uwsgi flv" PHP_TARGETS="php5-3" RUBY_TARGETS="ruby18 ruby19" USERLAND="GNU" VIDEO_CARDS="vesa nvidia nouveau" 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, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LC_ALL, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS, USE_PYTHON
Some people recommend trying to disable color management filter, but it didn't change anything for me.
Unfortunately something GIMP is doing is resulting in a software fallback. Since we don't have the source to the drivers we're not going to be able to dig into why this is happening. Your best option is to contact NVIDIA at linux-bugs@nvidia.com and explain everything and they can try to profile it.
