Okay, hold the phone. If you're going to compare things in a scientific manner, at least give the question mark variation a fighting chance: 
#!/usr/bin/perl -w

use strict;

use Benchmark 'cmpthese';

my @string = (
        "foofoo catbar",
        "foofoofoo catbar",
        "foo foo cat bar",
        "foo flew over the",
        "cufoofoo nest",
);

cmpthese(50_000, {
        foo_or => sub { /^(foob|)foofoo/ foreach (@string) },
        foo_qs => sub { /^(foob)?foofoo/ foreach (@string) }
});

[download]
With that in mind, the results are different: 
Benchmark: timing 50000 iterations of foo_or, foo_qs...
    foo_or:  2 wallclock secs ( 1.28 usr +  0.00 sys =  1.28 CPU) @ 39
+062.50/s (n=50000)
    foo_qs:  2 wallclock secs ( 1.21 usr +  0.00 sys =  1.21 CPU) @ 41
+322.31/s (n=50000)
          Rate foo_or foo_qs
foo_or 39062/s     --    -5%
foo_qs 41322/s     6%     --

[download]
The variance changes, but the question mark wins every time.

In reply to Re: Difference between (foo|) and (foo)? by tadman
in thread Difference between (foo|) and (foo)? by Derek2

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