Concerns about performance w/Python, Pysco on Pentiums

Skip Montanaro skip at
Fri Mar 7 23:41:24 CET 2003

    Peter> Py2.2, list, inlined:        16468, 108%
    Peter> Py2.3, list, inlined:        19074, 126%
    Peter> Py2.2, list, inlined, Psyco:  9963,  66% (!) 

    Peter> Not sure what that last one indicates, except that under certain
    Peter> circumstances (perhaps when used by someone who hasn't even read
    Peter> it's documentation? :-), Psyco can produce *worse* results.

How exactly are you using Psyco?  If you let it figure out which routines to
specialize, it generally does a poor job.  If you know where your hotspots
are, you can tell it to just specialize those routines.

You might want to play around with the pystone benchmark a little.  It's
been awhile since I ran the experiment, but I believe the critical routine
is pystone.Proc8.  If you tell it to specialize just that one routine, the
speedup is much better than if you simply call psyco.jit() and let Psyco
figure out what to do.


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