[Python-Dev] Optimization targets - refcount

[Paul Prescod]

Jewett, Jim J wrote:

> 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.  

So instead of writing Py_DECREF(foo) would we write code like

if(foo!=Py_None&&foo!=Py_Neg1&&foo!=Py_Zero&&foo!=PyOne){
	Py_DECREF(foo);
}

  Paul Prescod