I'm not convinced that this change should be merged. The benefit is small, and 1) it is only for an artificial set of tiny files, 2) the benchmarking ignores the real IO, it measures the work with a cache. When copy real files (/usr/include or Lib/) with dropped caches the difference is insignificant. On other hand, this optimization makes the code more complex. It can make the case with specifying the ignore argument slower.