禁用 glxgear 的垂直同步

有时您需要检查 Linux 3D 加速是否真正工作(除了 glxinfo输出)。这可以通过 glxgears工具快速完成。然而，FPS 通常仅限于显示器的垂直刷新率(即60 FPS)。因此，这个工具或多或少变得无用，因为即使是一个软件渲染也可以轻松地在现代 CPU 上生成60 FPS 的 glxgear。

我发现很难找到一个快速简单的解决方案，我回答了我自己的问题。希望能节省你的时间。

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最佳答案

The vblank_mode environment variable does the trick. You should then get several hundreds FPS on modern hardware. And you are now able to compare the results with others.

$>   vblank_mode=0 glxgears
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Disabling the Sync to VBlank checkbox in nvidia-settings (OpenGL Settings tab) does the trick for me.

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For Intel graphics and AMD/ATI opensource graphics drivers

Find the "Device" section of /etc/X11/xorg.conf which contains one of the following directives:

  • Driver "intel"
  • Driver "radeon"
  • Driver "fglrx"

And add the following line to that section:

Option     "SwapbuffersWait"       "false"

And run your application with vblank_mode environment variable set to 0:

$ vblank_mode=0 glxgears

For Nvidia graphics with the proprietary Nvidia driver

$ echo "0/SyncToVBlank=0" >> ~/.nvidia-settings-rc

The same change can be made in the nvidia-settings GUI by unchecking the option at X Screen 0 / OpenGL Settings / Sync to VBlank. Or, if you'd like to just test the setting without modifying your ~/.nvidia-settings-rc file you can do something like:

$ nvidia-settings --load-config-only --assign="SyncToVBlank=0"  # disable vertical sync
$ glxgears  # test it out
$ nvidia-settings --load-config-only  # restore your original vertical sync setting
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For intel drivers, there is also this method

Disable Vertical Synchronization (VSYNC)

The intel-driver uses Triple Buffering for vertical synchronization, this allows for full performance and avoids tearing. To turn vertical synchronization off (e.g. for benchmarking) use this .drirc in your home directory:

<device screen="0" driver="dri2">
<application name="Default">
<option name="vblank_mode" value="0"/>
</application>
</device>
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If you're using the NVIDIA closed-source drivers you can vary the vertical sync mode on the fly using the __GL_SYNC_TO_VBLANK environment variable:

~$ __GL_SYNC_TO_VBLANK=1 glxgears
Running synchronized to the vertical refresh.  The framerate should be
approximately the same as the monitor refresh rate.
299 frames in 5.0 seconds = 59.631 FPS


~$ __GL_SYNC_TO_VBLANK=0 glxgears
123259 frames in 5.0 seconds = 24651.678 FPS

This works for me on Ubuntu 14.04 using the 346.46 NVIDIA drivers.

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I found a solution that works in the intel card and in the nvidia card using Bumblebee.

> export vblank_mode=0
glxgears
...
optirun glxgears
...
export vblank_mode=1

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Putting the other answers all together, here's a command line that will work:

env vblank_mode=0 __GL_SYNC_TO_VBLANK=0 glxgears

This has the advantages of working for both Mesa and NVidia drivers, and not requiring any changes to configuration files.


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