  We propose a general method to operationally quantify the resourcefulness of
quantum channels via channel discrimination, an important information
processing task. A main result is that the maximum success probability of
distinguishing a given channel from the set of free channels by free probe
states is exactly characterized by the resource generating power, i.e. the
maximum amount of resource produced by the action of the channel, given by the
trace distance to the set of free states. We apply this framework to the
resource theory of quantum coherence, as an informative example. The general
results can also be easily applied to other resource theories such as
entanglement, magic states, and asymmetry.
