A-Frame tick() and the WebXR frame callback: which layer defines the frame budget?
On an A-Frame 1.x scene, the goal before optimizing is to locate the actual frame bottleneck rather than guess. Two timing sources sit at the integration boundary: the stats component, which times the ECS tick() loop on the CPU, and the WebXR session's frame callback, which delivers an XRFrame timestamp tied to the compositor's schedule. The two loops are no