Manually perform subexpression elimination in tight loops as often as you practically can. It can make quite a bit of difference in a CPU-bound script. (Remember -- 25% is the difference between an hour and 45 minutes.)
Please be very, very carefully with drawing conclusions. You have performed a benchmark, with one specific set of data, using a specific versions of Perl, for a specific version of a certain OS, running on a specific set of hardware. All you have proven so far is that with this particular combination of data, OS, perl version and hardware, you have a 25% gain. For someone else, using a different OS, a different CPU, or a different version of Perl, the numbers might be different.

Note also that a 25% improvement in an very, very simple loop seldomly translates to 25% improvement in the overall program. If only for the fact you'll typically do more in the loop.

In reply to Re: Perl and common subexpressions by Anonymous Monk
in thread Perl and common subexpressions by Stevie-O

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