Get CPU and GPU time in GDScript.

cpugputime.gd

# effectively stolen from https://github.com/godot-extended-libraries/godot-debug-menu credit to Calinou :D

# frametime_* is in milliseconds
# fps_*       is in frames per second (what else)

var viewport_rid = get_viewport().get_viewport_rid()
var frametime_cpu: int = RenderingServer.viewport_get_measured_render_time_cpu(viewport_rid) + RenderingServer.get_frame_setup_time_cpu()
var frametime_gpu: int = RenderingServer.viewport_get_measured_render_time_gpu(viewport_rid)
var fps_real: float = 1 / delta # assuming this is in _process, returns actual frame rate, capped at display refresh rate
var fps_theo: float = 1000 / max(frametime_cpu, frametime_gpu) # frame rate that could be attained if there was no FPS cap