use Benchmark qw(timethese) ;
sub op1 { my @one = 0 .. 10_000 ; my @two = 0 .. 10_000 ; }
sub op2 { my @one = 0 .. 10_000 ; @one = 0 .. 10_000 ; }
timethese( 1000, { op1 => 'op1', op2 => 'op2' } ) ;

Benchmark: timing 1000 iterations of op1, op2...
op1: 4 wallclock secs ( 3.20 usr + 0.00 sys = 3.20 CPU) @ 312.21/s (n=1000000)
op2: 6 wallclock secs ( 4.89 usr + 0.00 sys = 4.89 CPU) @ 204.46/s (n=1000000)

>>930と逆の結果っぽいんだけどなんで??
つか最後の
@ 312.21/s (n=1000000)と
@ 204.46/s (n=1000000)って
どっちが早いの？？