Michael Hudson <mwh21@cam.ac.uk> writes:
> Guido van Rossum <guido@digicool.com> writes:
>
> > Checking for a dup key in PyDict_SetItem() before calling dictresize()
> > slows things down. Checking in insertdict() is wrong because
> > dictresize() uses that!
>
> Maybe you could do the check for resize *after* the call to
> insertdict? I think that would work, but I wouldn't like to go
> messing with such a performance critical bit of code without some
> careful thinking.
Indeed; this tiny little patch:
Index: Objects/dictobject.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Objects/dictobject.c,v
retrieving revision 2.73
diff -c -r2.73 dictobject.c
*** Objects/dictobject.c 2001/01/18 00:39:02 2.73
--- Objects/dictobject.c 2001/03/20 13:38:04
***************
*** 496,501 ****
--- 496,508 ----
Py_INCREF(value);
Py_INCREF(key);
insertdict(mp, key, hash, value);
+ /* if fill >= 2/3 size, double in size */
+ if (mp->ma_fill*3 >= mp->ma_size*2) {
+ if (dictresize(mp, mp->ma_used*2) != 0) {
+ if (mp->ma_fill+1 > mp->ma_size)
+ return -1;
+ }
+ }
return 0;
}
fixes Ping's reported crash. You can't naively (as I did at first)
*only* check after the insertdict, 'cause dicts are created with 0
size.
Currently building from scratch to do some performance testing.
Cheers,
M.
--
It's a measure of how much I love Python that I moved to VA, where
if things don't work out Guido will buy a plantation and put us to
work harvesting peanuts instead. -- Tim Peters, comp.lang.python
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