#!/usr/bin/perl -w
use strict;
use Benchmark;

# Generate 1 MB of random data

my $data;
for (my $i = 0; $i < 1048576; $i++){
    $data .= chr int rand 256;
}
my $copy = $data;

# Remove X'es

Benchmark::cmpthese(-10, {
    's///'  => sub { $data =~ s/X//g; },
    'tr///' => sub { $copy =~ tr/X//d; }
});

print $copy eq $data ? "OK\n" : "NOT OK\n";