or download this
use Benchmark qw(:all);
use File::Slurp;
...
$read = sub { open $file, '<', 'arq.pdf' || die $!; read $file,
+$data, -s 'arq.pdf'; close $file; };
timethese(1000, { file_slurp => $file_slurp, read => $read, });
cmpthese(1000, { file_slurp => $file_slurp, read => $read, });