Physics Casting Performance

I started doing pathing and movement of charachters interacting with the environment, and was wondering about the performance of Ray, sphere, capsulrcasting, and the castAll methods. how intensive would it be to have a thread that did the constant physics casts from multiple characters out around them, and give the individual ai a structure detailing its environment?; so that it could path, or a player could wall run? what im asking about is the environment detection efficiency through Physics casting, not the interaction or AI or gameplay