  Energy consumption has been a great deal of concern in recent years and
developers need to take energy-efficiency into account when they design
algorithms. Their design needs to be energy-efficient and low-power while it
tries to achieve attainable performance provided by underlying hardware.
However, different optimization techniques have different effects on power and
energy-efficiency and a visual model would assist in the selection process.
  In this paper, we extended the roofline model and provided a visual
representation of optimization strategies for power consumption. Our model is
composed of various ceilings regarding each strategy we included in our models.
One roofline model for computational performance and one for memory performance
is introduced. We assembled our models based on some optimization strategies
for two widespread GPUs from NVIDIA: Geforce GTX 970 and Tesla K80.
