On Jun 24, 2013 9:11 PM, "Guido van Rossum" <gu...@python.org> wrote: > > On Mon, Jun 24, 2013 at 7:47 PM, Raymond Hettinger < raymond.hettin...@gmail.com> wrote: >> >> >> >> On Jun 24, 2013, at 4:07 AM, Victor Stinner <victor.stin...@gmail.com> wrote: >> >>> Out of curiosity, do you know (remember) how was the number 62 chosen? >>> Is it a compromise between memory usage and performances? 62 is >>> surprising because it is not a power of two :-) >>> >>> Is it to just have 64 (2+62) pointers in the structure? >> >> >> Yes, the goal was to have the struct size be an exact multiple >> of the cache line length (always a power-of-two, typically 64 bytes). >> What was different then is that deques weren't indexable. >> When indexing was added, the size of 62 became an >> unfavorable choice because it made the division and modulo >> calculation in deque_index() slower than for a power of two. > > > A-ha! Finally an explanation of the change. It makes intuitive sense now. I think the general feeling is that folks overreacted (perhaps confused by your silence) and that the reversal will be rolled back. Benjamin?
Seems likely to me. > > -- > --Guido van Rossum (python.org/~guido) > > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: http://mail.python.org/mailman/options/python-dev/greg%40krypto.org >
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