There is something wrong with this benchmark. I don't know what it is yet, but there is definitely something wrong.

Your numbers show, and I get the same results here, that Ike1 & Ike2 run in almost identical time.

This, despite that Ike1 loops twice as many times and make twice as many calls per loop to unpack and makes twice as many calls per loop to sysread. So 4 times as many calls to each over all, Ie 8 times as many calls in total!

That flies in the face of everything we know about performant Perl code. Sorry, but that simply cannot be true.