[Python-Dev] CPython optimization: storing reference counters outside of objects
Sturla Molden
sturla at molden.no
Tue May 24 14:25:59 CEST 2011
Den 24.05.2011 13:31, skrev Maciej Fijalkowski:
>
> Not sure what scenario exactly are you discussing here, but storing
> reference counts outside of objects has (at least on a single
> processor) worse cache locality than inside objects.
>
Artur Siekielski is not talking about cache locality, but copy-on-write
fork on Linux et al.
When reference counts are updated after forking, memory pages marked
copy-on-write are copied if they store reference counts. And then he
quickly runs out of memory. He wants to put reference counts and
PyObjects in different pages, so only the pages with reference counts
get copied.
I don't think he cares about cache locality at all, but the rest of us
do :-)
Sturla
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