If you look into strace of something like IMGUI demo on say sdl2+opengl backend, you'll see about same syscall/sec number at 60 fps, but it'll all be sequences of writev, recvmsg, poll, clock_gettime and DRM_IOCTL_SYNCOBJ_ ioctls. Which is basically just polling for input and submitting gpu command buffers, nothing expensive, and nothing a cache can help with.