[Python-Dev] int/float freelists vs pymalloc

Andrew MacIntyre andymac at bullseye.apana.org.au
Fri Feb 8 23:56:24 CET 2008

Tim Peters wrote:

> pymalloc ensures 8-byte alignment.  This is one plausible reason to
> keep the current int free list:  an int object struct holds 3 4-byte
> members on most boxes (type pointer, refcount, and the int's value),
> and the int freelist code uses exactly 12 bytes for each on most
> boxes.  To keep 8-byte alignment, pymalloc would have to hand out a
> 16-byte chunk per int object, wasting a fourth of the space (pymalloc
> always rounds up a requested size to a multiple of 8, and ensures the
> address returned is 8-byte aligned).

Hmmm... the funny thing is that the freelist approach is showing higher
memory consumption than the PyMalloc approach for the int case...

Andrew I MacIntyre                     "These thoughts are mine alone..."
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