On Sun, Nov 13, 2011 at 1:34 PM, Iustin Pop <ius...@debian.org> wrote: > On Thu, Nov 10, 2011 at 06:15:43PM +0100, Michel Dänzer wrote: >> On Don, 2011-11-10 at 18:01 +0100, Michal Suchanek wrote: >> > On 10 November 2011 17:46, Alex Deucher <alexdeuc...@gmail.com> wrote: >> > > On Wed, Nov 9, 2011 at 12:36 PM, Iustin Pop <ius...@debian.org> wrote: >> > >> >> > >> The recent upgrade of xserver-xorg-video-radeon from 1:6.14.2-2 to >> > >> 1:6.14.3-1 enabled ColorTiling for my card, which in turn caused a >> > >> significant performance degradation in 2D (yes, I understand it should >> > >> make 3D faster, but I didn't know it should slow down 2D applications). >> > >> >> > >> I'm using plain 2D environment (openbox, no compositing, anything) and >> > >> plain xterm (bitmap fonts, no AA, etc.). The speed of display text has >> > >> changed significantly enough that I can "see" my mutt refreshing the >> > >> inbox and drawing the lines. >> > > >> > > Tiling will speed up all rendering (2D and 3D). However, it sounds >> > > like you are using an environment that is mostly software rendering. >> > > As such in order for the CPU to access tiled buffers, the GPU has to >> > > copy them to a linear buffer before CPU can access it properly. >> > >> > FWIW I have color tiling enabled and have no speed issues in urxvt - >> > TrueType fonts, AA enabled, etc. >> > >> > Unlike xterm urxvt (rxvt-unicode) uses some special font-rendering >> > libraries, however. >> > >> > If I understand it correctly xterm would use the in-server bitmap font >> > rendering which the X server can accelerate as much as it wants. >> >> Core bitmap fonts are completely unaccelerated so far with EXA. xterm >> can also use Xft for font rendering via the -fa option though, which is >> well accelerated. > > Hi all, thanks for the replies. > > I've tested further and this seems to be a problem specific to xterm > (and possibly other software? not sure how to test e.g. firefox's UI > speed): > > Test file: ~20K lines. I've chosen the font sizes so as to have the same > number of lines in full-screen. The timing is simply "time cat file". > > ColorTiling disabled: > > xterm -fn fixed: ~3.3s > xterm -fa Mono -fs 8: ~8.6s > rxvt-unicode -fn fixed: ~0.07s > rxvt-unicode -fn xft:Mono:pixelsize=11: ~0.05s > > ColorTiling enabled: > > xterm -fn fixed: ~21s > xterm -fa Mono -fs 8: ~7.8s > rxvt-unicode -fn fixed: ~0.6s usually, sometimes ~0.1s?? > rxvt-unicode -fn xft:Mono:pixelsize=11: ~0.05s > > So it seems to me that: > > a) whatever xterm does, it is very sub-optimal > b) while xterm's -fa mode is indeed sped up by ColorTiling, it's still > many times slower than with ColorTiling disabled and using core > fonts > c) also rxvt-unicode with core fonts is slowed down by color tiling, > sometimes very much so (10x) > > Based on this I think this is mostly an xterm bug (-fa should/could be > much faster), but I wonder if it also applies to other purely software > 2D rendering.
It likely does. We optimize the accelerated paths rather than the slow paths. Alex -- To UNSUBSCRIBE, email to debian-x-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/cadnq5_nrxqyyw63re830m1nxojv63p8t5vdmj1biruxuwsu...@mail.gmail.com
