sub use_substr {
        my $string = shift;
        $string .= substr($string, -1) eq "/" ? "" : "/";
        return $string;
}
sub use_if_substr {
        my $string = shift;
        $string .= '/' if substr($string, -1) ne "/";
        return $string;
}

sub use_if_regex {
        my $string = shift;
        $string .="/" if(not $string =~/\/$/ );
        return $string;
}

sub use_regex {
        my $string = shift;
        $string =~ s|/?$|/|;
        return $string;
}

use Benchmark 'cmpthese';

my @strings = ( qw( a / sdf/ /some/path /another/path/ sdfasdfasdfsdafsadfasdfsfdsadfsdfsdfsadfasdfsadfsadfsadfsadfsdfsadfasfsdafasdfsdf ), 'some string with spaces in it' );

cmpthese ( 100000, {
        'if_substr' => sub { use_if_substr($_) for @strings },
        'substr'    => sub { use_substr($_)    for @strings },
        'if_regex'  => sub { use_if_regex($_)  for @strings },
        'regex'     => sub { use_regex($_)     for @strings }
} );