Yes, same computer. I just reran the tests (3 times each, one after the other), and got the same results as before: 
>c:\progs\perl588\bin\perl 674979.pl
                Rate class_nodot       class     literal
class_nodot   3037/s          --        -24%       -100%
class         4008/s         32%          --       -100%
literal     859954/s      28218%      21354%          --

>c:\progs\perl588\bin\perl 674979.pl
                Rate class_nodot       class     literal
class_nodot   3041/s          --        -26%       -100%
class         4087/s         34%          --       -100%
literal     868745/s      28464%      21158%          --

>c:\progs\perl588\bin\perl 674979.pl
                Rate class_nodot       class     literal
class_nodot   3041/s          --        -26%       -100%
class         4117/s         35%          --       -100%
literal     834248/s      27329%      20162%          --

>c:\progs\perl5100\bin\perl 674979.pl
                Rate class_nodot     literal       class
class_nodot 667282/s          --        -10%        -11%
literal     741037/s         11%          --         -1%
class       747754/s         12%          1%          --

>c:\progs\perl5100\bin\perl 674979.pl
                Rate class_nodot     literal       class
class_nodot 667704/s          --        -10%        -12%
literal     742924/s         11%          --         -2%
class       758776/s         14%          2%          --

>c:\progs\perl5100\bin\perl 674979.pl
                Rate class_nodot     literal       class
class_nodot 657342/s          --        -11%        -14%
literal     740217/s         13%          --         -3%
class       766213/s         17%          4%          --

[download]

So yes, something is slower. Not necessarily the regexp, but it's likely.

In reply to Re^3: The cost of unchecked best practices by ikegami
in thread The cost of unchecked best practices by moritz

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