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Enabling all optimization i got ~130fps without any magic and patches.
I suspect it is the radeon.pcie_gen2=1 setting. The problem is with pcie_gen2 enabled I won't get lightsmark to run. The setting seems to be still not stable. But there is a minimal (2-3 fps) increase with warsow.
Also running recent vdrift version with -gl2 option at 1920x1080 and vblank_mode=0 will almost double the frame rate from 17fps towards 30fps. That is 50-60% performance compared to windows which is quite impressive.
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.
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"?