use strict;
use warnings 'all';
 
use Benchmark 'cmpthese';

$::a = "foo-bar";
cmpthese -5 => {
    sub  =>  sub {$::a =~ /([-])/},
    str  =>      '$::a =~ /([-])/',
};
__END__
Benchmark: running str, sub for at least 5 CPU seconds...
       str:  5 wallclock secs ( 5.34 usr +  0.00 sys =  5.34 CPU) @ 390154.68/s (n=2083426)
       sub:  5 wallclock secs ( 5.13 usr +  0.00 sys =  5.13 CPU) @ 282139.18/s (n=1447374)
        Rate  sub  str
sub 282139/s   -- -28%
str 390155/s  38%   --