Sorry,  forgot to format that.

Finally,  here's your initial test (unaltered),   run on my own machine for base-line comparison:

ddouville@linuxdld:~> ./test2.pl
Benchmark: timing 1000000 iterations of c_foob0or1, c_foobOrNowt, foob0or1, foobOrNowt...
c_foob0or1:  2 wallclock secs ( 1.92 usr +  0.00 sys =  1.92 CPU) @ 520833.33/s (n=1000000)
c_foobOrNowt:  1 wallclock secs ( 1.78 usr +  0.00 sys =  1.78 CPU) @ 561797.75/s (n=1000000)
  foob0or1:  0 wallclock secs ( 1.33 usr +  0.00 sys =  1.33 CPU) @ 751879.70/s (n=1000000)
foobOrNowt:  1 wallclock secs ( 1.34 usr +  0.00 sys =  1.34 CPU) @ 746268.66/s (n=1000000)
                 Rate   c_foob0or1 c_foobOrNowt   foobOrNowt     foob0or1
c_foob0or1   520833/s           --          -7%         -30%         -31%
c_foobOrNowt 561798/s           8%           --         -25%         -25%
foobOrNowt   746269/s          43%          33%           --          -1%
foob0or1     751880/s          44%          34%           1%           --

These test results agree with your test results,  supporting that your results are correct for the test you performed.