[Patches] [ python-Patches-597907 ] Oren Tirosh's fastnames patch
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Mon, 02 Sep 2002 12:59:38 -0700
Patches item #597907, was opened at 2002-08-20 19:20
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Category: Core (C code)
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Guido van Rossum (gvanrossum)
Assigned to: Guido van Rossum (gvanrossum)
Summary: Oren Tirosh's fastnames patch
Initial Comment:
Oren Tirosh had a nice patch to *really* speed up
global/builtin name lookup. I'm adding it here because
I don't want to lose this idea.
His code and some comments are here:
http://www.tothink.com/python/fastnames/
I'm uploading a new version of this patch relative to
current CVS.
I'm still considering whether to do this; I measure at
best a 1% speedup for pystone.
For a modified version of Oren's benchmark (modified to
use a function instead of a class for 'builtin' and
'global', so that these tests use LOAD_GLOBAL rather
than LOAD_NAME, I get these test results (best of 3):
builtin 1.38
global 1.54
local 1.28
fastlocal 0.90
Python 2.3 without his patch (but with my speedup hacks
in LOAD_GLOBAL):
builtin 1.80
global 1.52
local 1.77
fastlocal 0.91
Python 2.2 (from the 2.2 branch, which is newer than
the 2.2.1 release but doesn't have any speedups) did this:
builtin 2.28
global 1.86
local 1.80
fastlocal 1.10
I don't care about the speedup for the 'local' case,
since this uses the LOAD_NAME opcode which is only used
inside class definitions; the 'builtin' and 'global'
cases are interesting. It looks like Oren's patch gives
us a nice speedup for looking up a built-in name from a
function. I have to think about why looking up a global
from a function is slower though...
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Comment By: Oren Tirosh (orenti)
Date: 2002-09-02 19:59
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I'm working on an improved version. Stay tuned!
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Comment By: Guido van Rossum (gvanrossum)
Date: 2002-08-20 19:31
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Tim explained why the 'globals' case is faster than the
'builtins' case. I used 'x' as the global to look up rather
than 'hex', and it so happens that the last three bits of
hash('x') and hash('MANY') are the same -- MANY is an
identifier I insert in the globals. I'll attach the test
suite I used (with 'hex' instead of 'x'). Now I get these times:
builtin 1.39
global 1.28
local 1.29
fastlocal 0.91
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