in reply to Re^2: $x = `cat big_file` seg faults
in thread $x = `cat big_file` seg faults

You are right. Repeated experiments show comparable times across Perl versions.

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

In Section Seekers of Perl Wisdom