Tim Peters wrote:
>
> [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>.
Looks like Jeremy's machine has a problem or this is the result
of different compiler optimizations. On my machine using the same
compiler and optimization settings I get the following figure for
DictCreation (2.1a1 vs. 2.0):
DictCreation: 1869.35 ms 12.46 us +8.77%
That's below noise level (+/-10%).
> 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.
Hmm, seemed like a natural explanation from looking at the code.
So now we have two different explanations for a non-existing
problem ;-)
I'll rerun the benchmark for 2.1a2 and let you know of the
findings.
--
Marc-Andre Lemburg
______________________________________________________________________
Company: http://www.egenix.com/
Consulting: http://www.lemburg.com/
Python Pages: http://www.lemburg.com/python/
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4