A GTK 4 application showing an empty window uses about 160 MB of RAM:

$ wget https://movq.de/v/138ab3e622/win.c
$ cc -Wall -Wextra -o win win.c $(pkg-config --cflags --libs gtk4)
$ ./win

It also takes several seconds to start on my machine because it is compiling shaders and initializing DRI (it’s faster on the second run, unless you happen to lose ~/.cache/mesa_shader_cache/). This might be a hint as to why it’s using so much memory: There’s obviously much more going on behind the scenes these days, not just a little bit of internal housekeeping and then creating a window.

@movq@www.uninformativ.de
Doesn’t even compile on my system, which is apparently broken:

> cc -Wall -Wextra -o win win.c $(pkg-config --cflags --libs gtk4)                                                                                                        
cc: error: unrecognized argument in option ‘-mfpmath=sse -msse -msse2 -pthread -I/usr/include/gtk-4.0 -I/usr/include/gio-unix-2.0 -I/usr/include/cairo -I/usr/include/pango-1.0 -I/usr/include/harfbuzz -I/usr/include/pango-1.0 -I/usr/include/fribidi -I/usr/include/harfbuzz -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/x86_64-linux-gnu -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/uuid -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/graphene-1.0 -I/usr/lib/x86_64-linux-gnu/graphene-1.0/include -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -lgtk-4 -lpangocairo-1.0 -lpango-1.0 -lharfbuzz -lgdk_pixbuf-2.0 -lcairo-gobject -lcairo -lgraphene-1.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0’
cc: note: valid arguments to ‘-mfpmath=’ are: 387 387+sse 387,sse both sse sse+387 sse,387

@movq@www.uninformativ.de If I understand it correctly, gtk4 renders using OpenGL. That means some of that RAM that appears to be allocated is actually some trick of the OpenGL driver so that it can map address in RAM space to the GPU’s VRAM (depends a lot on your setup though).

What happens if you run it with GSK_RENDERER=cairo set?