[Python-Dev] insertdict slower?

[Tim Peters]

[Tim]
> ... to the contrary, it said lookdict got 4.5% *faster* in 2.1.

Ack, I was reading the wrong column.  It actually said that lookdict went
from 0.48 to 0.49 seconds, while insertdict went from 0.20 to 0.26.

http://mail.python.org/pipermail/python-dev/2001-February/012428.html

Whatever, the profile isn't pointing at things that make sense, and is
pointing at things that don't.

Then again, why anyone would believe any output from a computer program is
beyond me <wink>.

needs-sleep-ly y'rs  - tim


PS:  Sorry to say it, but rich comparisons have nothing to do with this
either!  Run your dict creation test under a debugger and watch it -- the
rich compares never get called.  The basic reason is that hash(i) == i for
all Python ints i (except for -1, but you're not using that).  So the hash
codes in your dict creation test are never equal.  But there's never a
reason to call a "real compare" unless you hit a case where the hash codes
*are* equal.  The latter never happens, so neither does the former.  The
insert either finds an empty slot at once (& so returns immediately), or
collides.  But in the latter case, as soon as it sees that ep->me_hash !=
hash, it just moves on the next slot in the probe sequence; and so until it
does find an empty slot.