Distribution also favors the push model over the pull model. As discussed earlier, push requires a single, one-way communication, whereas pull requires three. When the distribution is implemented via RPCs (Remote Procedure Calls), push requires one call (Update()), whereas pull requires at least two calls (Update() and GetState()). RPCs have more overhead than nondistributed method invocations, so the extra calls required by the push approach can quickly hurt performance.
