We experimentally measure the eye diagram of an all-optical header processor using a crosscorrelator to achieve picosecond resolution. By varying 100-Gb/s header packets, we measure an eye diagram with a Q-value of 7.1 at 12-pJ packet pulse energy for the all-optical header processor consisting of all-optical logic gates and synchronized fiber lasers, From the Q-value, we also statistically calculate the potential hit-error-rate performance of 7.0 x 10-(13), By measuring the change in Q-values as a function of input power, we find that input power fluctuations degrade the performance of the header processor by reducing the switching contrast of the logic gates in the header processor.