[issue14520] Buggy Decimal.__sizeof__
report at bugs.python.org
Mon Apr 9 18:54:38 CEST 2012
Stefan Krah <stefan-usenet at bytereef.org> added the comment:
Mark Dickinson <report at bugs.python.org> wrote:
> In the C version of decimal, do distinct Decimal objects ever share coefficients?
The coefficients are members of the mpd_t struct (libmpdec data type),
and they are not exposed as Python objects or shared.
Cache locality is incredibly important: I have a patch that reserves
a static coefficient of four words inside the PyDecObject. This patch
speeds up _decimal by roughly another 30-40% for regularly sized decimals.
If the decimal grows beyond that, libmpdec automatically switches to
a dynamically allocated coefficient.
I think sharing would probably slow things down a bit.
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