Install OSD Cat:
sudo dnf install xosd
Run the game:
WINEDEBUG=+fps wine mygame.exe 2>&1 | tee /dev/stderr | \
grep --line-buffered "^trace:fps:" | osd_cat --lines="2"
You should see two red lines displaying the framerates.
The last one swapchain_gl_present
should be the correct value of your framerate.
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