[Python-Dev] Opcode frequency

Raymond Hettinger python at rcn.com
Thu Jun 19 01:03:19 CEST 2008

> Maciej Fijalkowski did an opcode analysis for PyPy,
> it also shows the relative frequency of opcodes following a
> specifc one:
> http://codespeak.net/svn/user/fijal/opcodes.txt
> Might it make sense to add more PREDICT()ions based
> on this, e.g. for BUILD_SLICE -> BINARY_SUBSCR?

This particular one might be okay.  What code generates it?
Are there other possible successors to BUILD_SLICE?
What code generates those?

There were lots of other opcode pairings that were previously
studied and rejected.  You're going over well traveled ground.

Also, opcode analysis is a somewhat hazardous undertaking.
Dynamic analysis takes into account which codes tend to
occur more often inside loops but it is *very* sensitive
to who wrote the app and their coding style.  These results
always have to be taken with a grain of salt. 


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