Next time, test your code. It doesn't even want to compile with 'use strict', and produces rubbish otherwise. Here's a tested version:

my @sorted =
    map $_->[0],
    sort {
      for (1..1000) {
        return @$a <=> @$b if $_ > $#$a or $_ > $#$b;
        $_ and return $_ for $a->[$_] <=> $b->[$_];
      }
    } map [$_, split /\s+/], @inputdata;
[download]

BTW, what's a GSR?

Abigail