Announcement

Collapse
No announcement yet.

The May 2012 Open-Source Radeon Graphics Showdown

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • phoronix
    started a topic The May 2012 Open-Source Radeon Graphics Showdown

    The May 2012 Open-Source Radeon Graphics Showdown

    Phoronix: The May 2012 Open-Source Radeon Graphics Showdown

    Up for publishing today is a multi-card multi-driver comparison spanning several generations of discrete ATI/AMD Radeon graphics cards looking at the Radeon OpenGL performance as found by default in Ubuntu 12.04, as found when updating to the latest "Git" development code, when tweaking the latest development code for maximum performance, and finally when using the proprietary AMD Catalyst Linux display driver.

    http://www.phoronix.com/vr.php?view=17370

  • agd5f
    replied
    Originally posted by phred14 View Post
    What is a "flip queue", (I can start guessing, but I'd like to see a non-guess.)
    See comment #47. You basically render as fast as you can and queue up completed frames for display so there is less waiting for flips compared to double buffering. It's basically triple or more buffering.

    Originally posted by phred14 View Post
    and why can't it be done in X/mesa/drivers?
    It can, it's just a lot of work.

    Leave a comment:


  • phred14
    replied
    What is a "flip queue", (I can start guessing, but I'd like to see a non-guess.) and why can't it be done in X/mesa/drivers?

    My guess says that you render off-screen, and put a pointer to that off-screen buffer into a "flip queue". Then during each blank interval they display the most recent entry and discard any stale entries. That then says that compositing might be a part of this.

    Will Wayland/Weston correspond more directly to the "more advanced presentation layer"?

    Leave a comment:


  • agd5f
    replied
    Originally posted by phred14 View Post
    But why are Windows people not griping about performance vs tearing?

    I understand that the problem is generic, but Windows appears to have had it solved long ago. Why is that solution so elusive for Linux?
    Windows supports flip queues and a much more advanced presentation layer, the open source stack does not yet.

    Leave a comment:


  • phred14
    replied
    But why are Windows people not griping about performance vs tearing?

    I understand that the problem is generic, but Windows appears to have had it solved long ago. Why is that solution so elusive for Linux?

    Leave a comment:


  • agd5f
    replied
    Originally posted by log0 View Post
    Btw does anyone know why tear-free display is so expensive (on linux) reducing the fps by a factor of two?
    It's not a Linux problem per se. Tear-free is slow because you can only flip between frames as fast as the refresh rate on your monitor. If you miss a vblank window, you half the FPS because the next flip won't happen until the next vblank period. The next frame has to wait until the flip happens before it can render. For smoother vblanked rendering you really need a flip queue rather than just double buffering. The app then renders frames as fast as it can and the completed frames enter the queue to be displayed and there is no waiting for the previous flip.

    Leave a comment:


  • log0
    replied
    Just retested vdrift with/without vblank_mode=0 and am getting 30fps for both. WTF...

    Leave a comment:


  • log0
    replied
    Btw does anyone know why tear-free display is so expensive (on linux) reducing the fps by a factor of two?

    Leave a comment:


  • log0
    replied
    Originally posted by curaga View Post
    That depends on whether your Windows number teared too. If you get 60% tearing compared to Windows tearfree, it's not so great.
    I've noticed no tearing(racing game). But I've noticed the difference between almost unplayable 17 and fluid 30fps...

    Leave a comment:


  • curaga
    replied
    That is 50-60% performance compared to windows which is quite impressive.
    That depends on whether your Windows number teared too. If you get 60% tearing compared to Windows tearfree, it's not so great.

    Leave a comment:

Working...
X