use strict;
use warnings;
use Devel::Peek;
use Benchmark qw/ cmpthese timeit /;

our @a = map log, 2..1e6; 
push @a, 0/1;
print "************   a   ************\n";
Dump $a[-2];
Dump $a[-1];
my @b = map $_ * 4, @a;
print "************   b   ************\n";
Dump $b[-2];
Dump $b[-1];
 
cmpthese( -2, {
    1 => 'my @c = map $_ * 4, @a',
    2 => 'my @c = map $_ / (1/4), @a',
});

__END__

************   a   ************
SV = NV(0x55f0580) at 0x55f0598
  REFCNT = 1
  FLAGS = (NOK,pNOK)
  NV = 13.8155105579643
SV = NV(0x102a388) at 0x102a3a0
  REFCNT = 1
  FLAGS = (NOK,pNOK)
  NV = 0
************   b   ************
SV = NV(0xae879c8) at 0xae879e0
  REFCNT = 1
  FLAGS = (NOK,pNOK)
  NV = 55.2620422318571
SV = PVNV(0x714ec8) at 0xae879f8
  REFCNT = 1
  FLAGS = (IOK,pIOK)
  IV = 0
  NV = 0
  PV = 0
    Rate    1    2
1 10.3/s   -- -20%
2 12.8/s  25%   --