use strict;
use warnings;
use PDL;
use Storable 'dclone';
use Benchmark 'cmpthese';

for my $size ( 4 .. 8 ) {
    print "*** string size is 1E$size bytes\n";

    my $data = byte( 256 * random( 10 ** $size ));
    my $buf  = $data-> get_dataref;

    cmpthese( -2, {
        copy   => sub { $data-> copy-> get_dataref },
        dclone => sub { dclone $buf },
        concat => sub { \( ${ $buf } . '' )},
    });
    print "\n";
}
__END__

Perl executable: C:\berrybrew\strawberry-perl-5.32.0.1-64bit-PDL\perl\bin\perl.exe
Perl version   : 5.32.0 / MSWin32-x64-multi-thread
PDL version    : 2.021

*** string size is 1E4 bytes
            Rate   copy dclone concat
copy     56875/s     --   -72%   -95%
dclone  201992/s   255%     --   -83%
concat 1182933/s  1980%   486%     --

*** string size is 1E5 bytes
           Rate   copy dclone concat
copy     7703/s     --   -90%   -94%
dclone  76109/s   888%     --   -43%
concat 134245/s  1643%    76%     --

*** string size is 1E6 bytes
         Rate   copy dclone concat
copy    808/s     --   -82%   -83%
dclone 4538/s   462%     --    -4%
concat 4713/s   484%     4%     --

*** string size is 1E7 bytes
         Rate   copy concat dclone
copy   67.8/s     --   -70%   -71%
concat  228/s   236%     --    -1%
dclone  230/s   240%     1%     --

*** string size is 1E8 bytes
         Rate   copy dclone concat
copy   6.84/s     --   -69%   -69%
dclone 21.8/s   219%     --    -1%
concat 22.1/s   223%     1%     --