Why are objects slower than procedural subs/data structs?

[Sol-Invictus]

what is it that makes objects 20-50% more expensive to use?

Originally posted as a Categorized Question.

[Fletch]

Method dispatch overhead. When you say foo( $a ) whatever foo in the current scope is called dirrectly. When you say $obj->bar( $b ), then perl has to check what $obj is (a scalar holding a blessed ref? a class name), then try and call Whatever::bar, and if that doesn't work try SuperWhatever::bar . . .

Granted there's some caching done, but it's more than just a simple subroutine call.

[pajout]

Object Methods Calls Versus Function Calls contains nicely described benchmarks. The simple reason is that it very depends on CPU-cost of subroutine bodies.