$s = '0123456789';
printf "%x\n", unpack 'Q', pack 'P', $s
    while $s =~ /\G./g;

# 55fd180fcc60
# 55fd18107f30
# 55fd18107ed0
# 55fd180e6700
# 55fd180fcc60
# 55fd18107f30
# 55fd18107ed0
# 55fd180e6700
# 55fd180fcc60
# 55fd18107f30


##</code><code>##

use strict;
use warnings;
use feature 'say';
use Config;

say "$^V / $Config{ archname }";

for my $len ( 1e4, 1e5, 1e6, 1e7 ) {
    my $s = 'a' x $len;

    my %h;
    my @before = times;
    $s =~ /\G./gs and ++ $h{ pack 'P', $s } 
        for 1 .. $len / 100;                    # do just 1% !!!
    my @after = times;

    printf "Length: %8d, addresses: %6d, user: %6g, system: %6g\n",
        $len, scalar( keys %h ), 
        $after[ 0 ] - $before[ 0 ],
        $after[ 1 ] - $before[ 1 ]
}

__END__

v5.40.3 / x86_64-linux-thread-multi
Length:    10000, addresses:      1, user:      0, system:      0
Length:   100000, addresses:      1, user:      0, system:      0
Length:  1000000, addresses:      1, user:   0.01, system:      0
Length: 10000000, addresses:      1, user:   0.02, system:      0

v5.42.0 / x86_64-linux-thread-multi
Length:    10000, addresses:      2, user:      0, system:      0
Length:   100000, addresses:      3, user:   0.01, system:      0
Length:  1000000, addresses:      3, user:   0.39, system:      0
Length: 10000000, addresses:      3, user: 139.87, system:      0

v5.43.8 / x86_64-linux
Length:    10000, addresses:      2, user:      0, system:      0
Length:   100000, addresses:      3, user:   0.01, system:      0
Length:  1000000, addresses:      3, user:   0.38, system:      0
Length: 10000000, addresses:      3, user: 138.75, system:   0.01

v5.42.0 / MSWin32-x64-multi-thread
Length:    10000, addresses:      2, user:      0, system:      0
Length:   100000, addresses:      2, user:      0, system:      0
Length:  1000000, addresses:      2, user:  0.844, system:  1.063
Length: 10000000, addresses:     70, user: 154.453, system: 253.812