[Python-Dev] Tunable parameters in dictobject.c (was dictnotes.txt out of date?) (original) (raw)

Maciej Fijalkowski fijall at gmail.com
Mon Jun 18 21:31:27 CEST 2012

On Mon, Jun 18, 2012 at 5:04 PM, Antoine Pitrou <solipsis at pitrou.net> wrote:

On Mon, 18 Jun 2012 15:28:24 +0100 Mark Shannon <mark at hotpy.org> wrote: > > But do they? The results of benchmarking would seem to suggest (at least > on my test machine) that overly-sparse dicts are slower. > Possibly due to increased cache misses.

Or, at least, they are not faster. See the synthetic experiments in http://bugs.python.org/issue10408 That said, Raymond might have witnessed different results at the time. Hardware evolves quickly and the parameters change (memory latency today is at least 50+ CPU cycles, which is quite a lot of wasted work on a pipelined superscalar CPU). Regards Antoine. More like 200-500 CPU cycles on modern CPUs. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20120618/4c11ea28/attachment.html>

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