[Patches] [ python-Patches-711722 ] Cache lookup of __builtins__

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Patches item #711722, was opened at 2003-03-29 01:47
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https://sourceforge.net/tracker/?func=detail&atid=305470&aid=711722&group_id=5470

Category: Core (C code)
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Raymond Hettinger (rhettinger)
Assigned to: Nobody/Anonymous (nobody)
Summary: Cache lookup of __builtins__

Initial Comment:
Rather than perform a bytecode optimization of 
LOAD_GLOBALS, takes an alternative approach of 
caching the lookup of builtins.

To be safe, it checks the cache only after trying a 
lookup in globals().  I can think of only one way to 
break this approach:  run the function accessing a 
builtin, then poke a new value into the builtins 
module, and then re-run the function:

def f(x):
    return oct(x)
print f(20)
__builtins__.oct = hex
print f(20)  # doesn't notice new def of oct()

The gives about a 2% speed-up to average programs, 
0% to programs that don't use builtins, and higher 
percentages to those with heavier use of builtins.  The 
speedup is limited by 1) having to still check globals 
and 2) the relative insignificance of builtin access time 
in most programs.  Still, it pretty much solves the 
problem of access time for builtins.




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