Originally posted by Mat2
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Radeon X.Org 7.4.0 Driver Brings More Tiling, R300/R500 GLAMOR
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Originally posted by agd5f View PostIt's not that the 2D engine is faster or that XAA or EXA accelerates more stuff. 2D and 3D engines have different capabilities. 2D engines can can basically do 3 things:
1. blit (move rectangles from one place to another)
2. fill (draw a filled rectangle)
3. lines
2D engines can't do coordinate transforms (scaling or rotation), alpha-blending, etc. so those operations require the 3D engine.
Core X and render were deisgned prior to GPU acceleration so a lot of ops map really poorly to modern hardware. Even today, pure software rendering is still faster than hw in many cases.
XAA only attempted to accelerate core X rendering. Additionally offscreen image support broken probably 6 or 7 years ago, so XAA only accelerated on screen images which means that for the most part, XAA almost always uses software rendering. Additionally, XAA was generally only exposed on older asics that had limited 3D engines, no support for tiled buffers, etc. Software fallbacks were relatively cheap on those cards for onscreen stuff and all offscreen buffers were rendered with software to begin with.
EXA took the most commonly used core X operations (blits and fills) and added limited support for also accelerating render (coordinate transforms, alpha blending, etc.).
For EXA, we use the 2D engine for blits and fills if the hw has it. For everything else, we use the 3D engine.
glamor accelerates core X and render using OpenGL.
EXA was introduced as a stopgap measure, to provide better integration with XRender than XAA did, improving the X.Org Server 2D performance. In practice, while this proved quite advantageous in some respects, it also exhibited a number of corner cases and regressions.
Don't know who write those WP article, but if i had to do that i will write nearly the same . Because i rememeber me reading and trying early EXA in comparation with xfree86 i was use at that time on i think Debian Sarge or something . It was quite of a (negative) difference when compared with that, basically that was being to me "Troltech's developer did it with QT3 in mind" i expected that of course and was got that corner cases being gtk2 slow, fltk slow, etc .
That was 9 years ago, but i clearly remember gtkperf was much faster than EXA on that very old r200 XAA, those results i had was actually being faster then i having today on modern hardware with xserver glamor (and that is considered tad fast by today standards or how glamor behave earlier) .Last edited by dungeon; 26 June 2014, 09:06 PM.
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Originally posted by dungeon View PostThat was 9 years ago, but i clearly remember gtkperf was much faster than EXA on that very old r200 XAA, those results i had was actually being faster then i having today on modern hardware with xserver glamor (and that is considered tad fast by today standards or how glamor behave earlier) .
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Originally posted by agd5f View PostTry comparing any X acceleration to software rendering. XAA is basically software rendering.
Anyway glamor works great in xserver 1.16 on kabini, kernel 3.16 made very good performance improvment ... i very appreciate what you developers do, other then inconsistent llvm by nature (seems to me that one needs more attention/work) i very much like how things works now .
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