use Benchmark;

timethese(250000, {
    one => sub {
        $string = "blah+blah+blah";
        $string =~ tr/+/ /;
    },
    two => sub {
        $string = "blah+blah+blah";
        $string =~ s/\+/ /g;
    }
});

print "\n";

timethese(2000000, {
    one => sub {
        $string = "blah+blah+blah";
        $string =~ tr/+/ /;
    },
    two => sub {
        $string = "blah+blah+blah";
        $string =~ s/\+/ /g;
    }
});