[Python-Dev] Optimization targets - refcount

[Jewett, Jim J]

Mike Pall:

> About GC: yes, refcounting is the silent killer.
>... Py_DECREF is awful ... > 3500 locations

Is it always needed?

What if a few common (constant, singleton) objects 
(such as None, -1, 0, 1) were declared immortal at 
compile-time?  They would be created at initial 
load in a special untracked pool, and their 
tp_dealloc would do nothing.

The slot for tracking references would still be
there, but could be ignored -- even if it went
negative.

Since the reference count no longer has to be
correct (for these objects), the reference 
counting macros could optimize to nothing when 
they know at compile time that they'll have one 
of these constant objects.  

-jJ