Update: Ok, not entirely useless: if you want a routine not to return to where you called it from, goto is the way to do it. In other words, use it when you want to do weird control flow (which is what goto is all about). Example:

sub one {
  print "In one\n";
  goto &two;
  print "never print this if you goto\n";
}

sub two {
  print "In two\n";
}

one();
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In fact I'm wrong in any case. A naive recursive call seems to be just a hair faster than the goto, even when finding the median of a million-element list.

As you suggest, the fastest of all is to simply call the sub with an ampersand, but really the difference is very small. I wonder whether this is running into unshift's worst-case performance.

Premature optimization and all that…