c:\test>p1
[0] Perl> 
sub shuffle { 
    my $r = shift; 
    for ( 0 .. $#$r ) { 
        my $a = $_ + rand( @$r - $_ ); 
        my $t = $r->[ $a ]; 
        $r->[ $a ] = $r->[ $_ ]; 
        $r->[ $_ ] = $t; 
    }; 
};;

[0] Perl> @a = 1 .. 1e6;;
[0] Perl> push @a, @a;;
[0] Perl> push @a, @a;;
[0] Perl> push @a, @a;;
[0] Perl> push @a, @a;;

[0] Perl> $t = time; shuffle \@a; print time - $t;;
20.9429998397827

[0] Perl> print total_size \@a;;
518218064

##</code><code>##

c:\test>p1
[0] Perl> sub shuffle { 
    my $r = shift; 
    my $n = length( $$r ) / 8; 
    for ( 0 .. $n ) { 
        my $a = $_ + rand( $n - $_ ); 
        my $t = substr $$r, $a, 8; 
        substr $$r, $a, 8, substr $$r, $_, 8; 
        substr $$r, $_, 8, $t; 
    }; 
};;

[0] Perl> $a = pack 'f*', map -1e5 + rand(1e9), 1 .. 1e6;;
[0] Perl> $a x= 96;;

[0] Perl> print length $a;;
384000000

[0] Perl> $t = time; shuffle \$a; print time - $t;;
59.6950001716614