  Efficient use of energy is essential for today's supercomputing systems, as
energy cost is generally a major component of their operational cost. Research
into "green computing" is needed to reduce the environmental impact of running
these systems. As such, several scientific communities are evaluating the
trade-off between time-to-solution and energy-to-solution. While the runtime of
an application is typically easy to measure, power consumption is not.
Therefore, we present the Power Measurement Toolkit (PMT), a high-level
software library capable of collecting power consumption measurements on
various hardware. The library provides a standard interface to easily measure
the energy use of devices such as CPUs and GPUs in critical application
sections.
