In the nvidia-settings app, there is a toggle called
[X] Enable Graphics API Visual Indicator
In the hover-help it states: “it shows whether the application is blitting or flipping.”
I enabled this indicator, and indeed see printed in my window the FPS, and BLIT - VSYNC ON.
Now, no matter what I set “Allow Flipping” to, all my apps always show BLIT, and never FLIP.
I am pretty sure the Indicator is broken, and not the actual FLIP setting.
Because my app does behave differently with Enable Flipping set to ON or OFF. If it is disabled, I see my app stutter at times. If I enable it, the stutter is gone.
Hence: the BLIT/FLIP toggle works. But the BLIT/FLIP indicator is broken.
OS: Linux x86 64 bit (Ubuntu 18.04.2 LTS)
GPU: GeForce GTX 1650
NV-CONTROL Version: 1.29
Is this an Optimus system?
No, it is a plain old desktop machine. Core i5 and the 1650 GPU is from Zotac Gaming.
Are you running a desktop composite manager? If you are, check whether it has an option to unredirect full-screen windows. It’s possible that the Allow Flipping checkbox is toggling whether your compositor is allowed to flip, but your application is always blitting into its redirected window.
If you can try running your application on a bare X server or with a basic non-compositing window manager such as Openbox, you should see it say that it’s flipping.
Thank you for the suggestion.
I tried running under ‘twm’ window manager, with same result.
I also tried running a bare ‘X’ process without a window manager, and even then, the Indicator states ‘BLIT’ for my app. I never see ‘FLIP.’
Oh, discard that!
If I run full-screen, and I use openbox, then I indeed see “FLIP.” If I run in a window, I see BLIT.
Thank you for your help.