1. A method for load balancing in a graphics processing system, the method comprising: for each of a plurality of rendering processes: assigning an identifier storage location from a first plurality of storage locations to be a first identifier storage location associated with the rendering process; assigning a portion of the rendering process to be performed by each of a plurality of graphics processors in the graphics processing system; instructing the graphics processors to perform the rendering process, wherein each graphics processor performs the portion of the rendering process assigned thereto; and instructing each of a first pair of the graphics processors to store, upon completion of the portion of the rendering process assigned thereto, a respective processor identifier in the first identifier storage location associated with the rendering process such that the processor identifier of the one of the first pair of the graphics processors that is last to complete the portion of the rendering process assigned thereto overwrites the processor identifier of the one of the first pair of the graphics processors that is first to complete the portion of the rendering process assigned thereto; and for at least the first pair of the graphics processors: determining, based on the processor identifiers stored in the first plurality of storage locations, whether an imbalance exists between respective loads of the first pair of graphics processors; and in the event that an imbalance exists, shifting a subset of the portion of the rendering process assigned to a more heavily loaded one of the first pair of graphics processors to the less heavily loaded one of the first pair of graphics processors.