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Thread: Catalyst vs. Mesa Performance With Ubuntu 10.04

  1. #21
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    Since you don't post images does it mean the image-quality is identical between the Radeon driver and Catalyst?

    Quote Originally Posted by Michael View Post
    If you look around, you'll see I never use the term "FOSS" in any Phoronix article anywhere.
    Why? Is Free/Libre not important?

  2. #22
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    Quote Originally Posted by numasan View Post
    Since you don't post images does it mean the image-quality is identical between the Radeon driver and Catalyst?
    It's a fairly unimportant point. He's likely not using XvBA on the Catalyst stack and there's no video decoding acceleration in the open stack at all. All he's really benchmarking is how much CPU power each driver requires for doing hardware accelerated image scaling and presentation.

  3. #23
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    Quote Originally Posted by zhasha View Post
    It's a fairly unimportant point. He's likely not using XvBA on the Catalyst stack and there's no video decoding acceleration in the open stack at all. All he's really benchmarking is how much CPU power each driver requires for doing hardware accelerated image scaling and presentation.
    He isn't talking about video image quality, but the quality of the 3d scene that is rendered. If one driver falls back and only displays half the complexity, then that's worth knowing about.

    But Michael already answered this in his post above - there were a few bugs rendering some of the textures, but it seemed to at least try to display everything so it seemed like they were doing about the same amount of work.

  4. #24
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    Quote Originally Posted by smitty3268 View Post
    He isn't talking about video image quality, but the quality of the 3d scene that is rendered. If one driver falls back and only displays half the complexity, then that's worth knowing about.

    But Michael already answered this in his post above - there were a few bugs rendering some of the textures, but it seemed to at least try to display everything so it seemed like they were doing about the same amount of work.
    The OpenGL spec doesn't allow us to decrease details. That's why we have stuff like piglit to test the conformance of the driver to the spec. Every pixel has to be perfectly on the money or it's simply wrong. By falling back, in driver terms we're speaking about using the CPU to emulate what the GPU can't do, and we generally don't want to do that either, but it still ALWAYS produces the correct result. If the result is not spot on, it's a driver bug and must be fixed.
    Of course there are border scenarios where for example we don't have a high enough precision register or whatever it may be that causes the color to be slightly off. Those are also perfectly consistent across all drivers as it's a hardware issue.
    Again, it's a completely moot thing to ask for.

  5. #25
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    Quote Originally Posted by zhasha View Post
    The OpenGL spec doesn't allow us to decrease details. That's why we have stuff like piglit to test the conformance of the driver to the spec. Every pixel has to be perfectly on the money or it's simply wrong. By falling back, in driver terms we're speaking about using the CPU to emulate what the GPU can't do, and we generally don't want to do that either, but it still ALWAYS produces the correct result. If the result is not spot on, it's a driver bug and must be fixed.
    Of course there are border scenarios where for example we don't have a high enough precision register or whatever it may be that causes the color to be slightly off. Those are also perfectly consistent across all drivers as it's a hardware issue.
    Again, it's a completely moot thing to ask for.
    The application can and often does fall back to rendering simpler scenes if it detects that the hardware (or driver) doesn't support certain functionality or is too slow to display the higher settings that the game supports. Not to mention the fact that the driver could simply be buggy and do a null op instead of what it actually should be doing.

  6. #26
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    Is the open-source driver finally catching up to AMD's highly optimized driver?

    Calling the catalyst a highly optimized driver is a bit over the top in my opinion. In fact, my ATi 9700 with the opensource mesa stack works much much better on a composite desktop than my HD4850 with the catalyst driver.

  7. #27
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    The "highly optimized" comments refer to the 3D stack AFAIK (OpenGL/Mesa), where a lot of code can be shared across OSes since the API is common.

    On the 2D side every OS has unique APIs and so the opportunity to share common code is much smaller.

  8. #28
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    Quote Originally Posted by bridgman View Post
    The "highly optimized" comments refer to the 3D stack AFAIK (OpenGL/Mesa), where a lot of code can be shared across OSes since the API is common.

    On the 2D side every OS has unique APIs and so the opportunity to share common code is much smaller.
    A composite desktop is one that is, and I'm not entierly sure of the engineering behind it, drawn via OpenGL. This is commonly done in Gnome by running Compiz or in KDE by toggling on the 3D effects in Kwin.
    So sure Docky is two dimentional but I'm quite sure it uses OpenGL to do it's opacity and texture effects. This along with Compiz effects results in very low framerates, something that is not present in the mesa implementation on my much much older card.

  9. #29
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    Quote Originally Posted by Rovanion View Post
    A composite desktop is one that is, and I'm not entierly sure of the engineering behind it, drawn via OpenGL. This is commonly done in Gnome by running Compiz or in KDE by toggling on the 3D effects in Kwin.
    So sure Docky is two dimentional but I'm quite sure it uses OpenGL to do it's opacity and texture effects. This along with Compiz effects results in very low framerates, something that is not present in the mesa implementation on my much much older card.
    try the no backfill patch for the xserver
    it will increase your composited desktop performacne drastically.

  10. #30
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    Making a window wobbly and drawing it on a cube doesn't mean you're gonna be running Crysis anytime soon. There is lots of stuff missing in the open source 3D drivers.

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