Update: a typo and factual error. Mis-read my own benchmark.

As (was:if) you know your files are not too big to fit in memory and you really need the speed, the add this to your benchmark. It beats your code by 400%60%. Standard perl.

 sub sub3 {
     open FILE, 'yourfile' or die $!;
     binmode FILE;
     my @lines =  split $/, do{ local $/; <FILE>; };
     close FILE or warn $!;
 }
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