GPUs are one of the most energy-consuming components for real-time rendering
applications, since a large number of fragment shading computations and memory
accesses are involved. Main memory bandwidth is especially taxing
battery-operated devices such as smartphones. Tile-Based Rendering GPUs divide
the screen space into multiple tiles that are independently rendered in on-chip
buffers, thus reducing memory bandwidth and energy consumption. We have
observed that, in many animated graphics workloads, a large number of screen
tiles have the same color across adjacent frames. In this paper, we propose
Rendering Elimination (RE), a novel micro-architectural technique that
accurately determines if a tile will be identical to the same tile in the
preceding frame before rasterization by means of comparing signatures. Since RE
identifies redundant tiles early in the graphics pipeline, it completely avoids
the computation and memory accesses of the most power consuming stages of the
pipeline, which substantially reduces the execution time and the energy
consumption of the GPU. For widely used Android applications, we show that RE
achieves an average speedup of 1.74x and energy reduction of 43% for the
GPU/Memory system, surpassing by far the benefits of Transaction Elimination, a
state-of-the-art memory bandwidth reduction technique available in some
commercial Tile-Based Rendering GPUs