  We discuss entropy production in nonequilibrium steady states by focusing on
paths obtained by sampling at regular (small) intervals, instead of sampling on
each change of the system's state. This allows us to study directly entropy
production in systems with microscopic irreversibility, for the first time. The
two sampling methods are equivalent, otherwise, and the fluctuation theorem
holds also for the novel paths. We focus on a fully irreversible three-state
loop, as a canonical model of microscopic irreversibility, finding its entropy
distribution, rate of entropy pr oduction, and large deviation function in
closed analytical form, and showing that the widely observed kink in the large
deviation function arises solely f rom microscopic irreversibility.
