Yes, I was talking about builtin Perl sort vs a Perl-coded high-water mark. Your List::Util's max doesn't apply in the referenced case (largest file), because max can't be coaxed to doing an indirection, so you'd need a GRT style translation, or else you're back to open coding it, again.

The point here is that high-water-mark is one strategy, and sorting is another strategy, with different costs depending on the length. The only real takeaway here is Benchmark will know, because you can't always guess.