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Gallium3D Now In Mainline Mesa Code-Base!

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  • #31
    Believe it or not, I do understand your point.

    I have one too -- that none of the really demanding Windows games are usefully running on Linux today, and that by the time they do you probably will like fglrx a lot better.


    • #32
      bridgman, you mention a good GLSL compiler being one major component missing. What are your thoughts on LLVM and its potential to shore up this weakness. Could it be done? At speed?


      • #33
        I think LLVM will be a great compiler in terms of being versatile and predictable. My only concern is not a criticism of LLVM per se, just an observation that most of the optimizing happens before instructions are emitted, which is fine for a normal CPU but not so fine for a superscalar machine.

        In the case of 6xx/7xx we use a 5-way superscalar instruction word (up to 5 independent operations per VLIW instruction) and I don't think LLVM's built in optimizations will be able to opimize for that. This is not a showstopper; it just means that either the code generator for 6xx/7xx will need to have some hard-coded optimization, or that someone will need to figure out how to make VLIW issues visible to the standard LLVM optimizers.

        In the meantime, we'll probably average something like 60% utilization of the superscalar hardware. The proprietary driver uses a very clever shader compiler which is able to achieve much higher utilization numbers.

        Big picture, my guess is that for a while all the drivers will use LLVM for software rendering (eg running vertex shaders on our pre-7xx IGP parts which don't have vertex shader hardware) and hard-code shader opcode emission for vertex and pixel shaders on GPU rather than using LLVM. Not sure about this, but it's my impression.
        Last edited by bridgman; 02-12-2009, 10:19 AM.


        • #34
          Originally posted by RealNC View Post
          I don't think he's testing Oblivion and Crysis and stuff
          It makes sense, too. The bottleneck with these is not your GPU, but the Wine D3D emulation layer. Quoting from WineHQ:Crysis:
          What does not
          The sound. Had to desable it to get passed the EA logo.
          The FPS. I get something like ~1FPS when I run this game perfectly on windows..
          Edit: Late reply, by about a whole page of posts...
          Last edited by BlackStar; 02-12-2009, 07:17 AM.