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AMD R600g Performance Patches Yield Mixed Results

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  • phoronix
    started a topic AMD R600g Performance Patches Yield Mixed Results

    AMD R600g Performance Patches Yield Mixed Results

    Phoronix: AMD R600g Performance Patches Yield Mixed Results

    Following performance benchmark results I published earlier this week comparing the open-source Radeon and AMD Catalyst driver performance under Ubuntu 12.10, Marek, the well-known independent open-source graphics driver developer, set out to explore some of the performance issues in the open-source driver. One day later, he published a patch that could quadruple the frame-rate of the Radeon Gallium3D driver. He went on to push another performance-focused patch too for this R600g driver. In this article are a fresh round of benchmarks of the open-source driver to look at the wins and losses attributed to this new code.

    http://www.phoronix.com/vr.php?view=18093

  • przemoli
    replied
    Originally posted by Leslie508 View Post
    How the heck is this mixed results?!
    Because of unfortunate selection of test profiles and with assumption that those bug reports are valid.


    You can only see one regression, but its due to fact that all other test cases used simpler 3d engine. Coupled with bug reports related to sophisticated 3d engines, "mixed results" is correct name. Though this article do not show it completely.

    Leave a comment:


  • Leslie508
    replied
    How the heck is this mixed results?!

    Leave a comment:


  • marek
    replied
    Originally posted by Drago View Post
    Marek, are there any plans for TTM refactoring, so it doesn't do these synchronizations?
    Not at the moment, though it's possible there are more issues with TTM. The memory fragmentation comes to mind right now, though I'm not really sure that's the issue.

    Leave a comment:


  • Drago
    replied
    Originally posted by marek View Post
    Here's some update. We believe the huge performance regression is actually caused by TTM. Put simply, it always synchronizes the CPU with the GPU before a buffer is moved, which is a total performance killer. I think it's a huge mistake that TTM does the synchronization at all, because it's completely unnecessary in our case.
    Marek, are there any plans for TTM refactoring, so it doesn't do these synchronizations?

    Leave a comment:


  • bridgman
    replied
    Originally posted by curaga View Post
    When did 512mb VRAM become low-end?
    Roughly 2-3 years ago -- I don't remember exactly when, but there was a point where most graphics card mfgs moved en masse to shipping 1GB as the standard configuration even though it wasn't really required at the time.

    Leave a comment:


  • curaga
    replied
    Originally posted by Lemonzest View Post
    Of course Xonotic is going to be texture starved on a low end 512MB card! they should run it again with a midrage 1GB card, like the 67xx/68xx cards
    When did 512mb VRAM become low-end?

    Leave a comment:


  • 89c51
    replied
    Originally posted by marek View Post
    Here's some update. We believe the huge performance regression is actually caused by TTM. Put simply, it always synchronizes the CPU with the GPU before a buffer is moved, which is a total performance killer. I think it's a huge mistake that TTM does the synchronization at all, because it's completely unnecessary in our case.
    BTW -and yes i am hijacking- you radeon people broke something in the latest stable kernels related to TTM/GEM.

    https://bugs.archlinux.org/task/32095#comment100850

    (and there is also another bug report in the kernel bugzilla related to this)

    Leave a comment:


  • marek
    replied
    Here's some update. We believe the huge performance regression is actually caused by TTM. Put simply, it always synchronizes the CPU with the GPU before a buffer is moved, which is a total performance killer. I think it's a huge mistake that TTM does the synchronization at all, because it's completely unnecessary in our case.

    Leave a comment:


  • Rigaldo
    replied
    Originally posted by Lemonzest View Post
    Of course Xonotic is going to be texture starved on a low end 512MB card! they should run it again with a midrage 1GB card, like the 67xx/68xx cards
    What's your point? It's performance significantly decreased on the same card, how does it have to do with the graphics RAM amount?

    Leave a comment:

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