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Author mark.dickinson
Recipients Rhamphoryncus, jcea, mark.dickinson, pitrou, rhettinger
Date 2009-02-11.12:27:59
SpamBayes Score 4.71995e-11
Marked as misclassified No
Message-id <1234355284.22.0.0469002855169.issue5186@psf.upfronthosting.co.za>
In-reply-to
Content
Here's an updated patch, that errs on the conservative side:

- rotate instead of shifting, as suggested by Raymond.  This costs
  very little, and I admit to feeling uncomfortable about the
  possibility of just throwing bits away 

- explicit check for -1

- special case for sizeof(void *) = 2*sizeof(long)

All tests pass with the patch applied.  I've left the 'convert to
PyLong' code in as a safety net: it's used on platforms where
sizeof(void *) > sizeof(long) but sizeof(void *) != 2*sizeof(long).  I
don't know of any such platforms in current use.

Sample timings on 64-bit linux (non-debug trunk build, Core 2 Duo).  

before:

dict creation (selected):  1.18751096725
dict creation (shuffled):  1.21234202385
dict creation:  1.00831198692
set creation (selected):  0.869561910629
set creation (shuffled):  0.867420911789
set creation:  0.77153301239

and after:

dict creation (selected):  1.06817317009
dict creation (shuffled):  0.987659931183
dict creation:  0.662216901779
set creation (selected):  0.735805034637
set creation (shuffled):  0.659453868866
set creation:  0.445232152939
History
Date User Action Args
2009-02-11 12:28:04mark.dickinsonsetrecipients: + mark.dickinson, rhettinger, jcea, Rhamphoryncus, pitrou
2009-02-11 12:28:04mark.dickinsonsetmessageid: <1234355284.22.0.0469002855169.issue5186@psf.upfronthosting.co.za>
2009-02-11 12:28:02mark.dickinsonlinkissue5186 messages
2009-02-11 12:28:01mark.dickinsoncreate