#!/usr/bin/perl -w
use strict;
use Benchmark qw(cmpthese);

sub xform {
        map {$_->[0]}
        sort { $a->[1] <=> $b->[1]} 
        map {[$_, rand(1)]} @_;
}

sub slice {
        my @random;
        push @random, rand 1 for 0 .. $#_;
        @_[ sort { $random[$a] <=> $random[$b] } 0 .. $#_ ];
}

my @array = 1 .. 1000;

cmpthese(1000, {
        slice => sub { slice @array },
        xform => sub { xform @array },
});

__END__

Benchmark: timing 1000 iterations of slice, xform...
     slice: 17 wallclock secs (16.96 usr +  0.08 sys = 17.04 CPU) @ 58.69/s (n=1000)
     xform: 28 wallclock secs (27.76 usr +  0.12 sys = 27.88 CPU) @ 35.87/s (n=1000)
        Rate xform slice
xform 35.9/s    --  -39%
slice 58.7/s   64%    --