Method much slower than function?

[Chris Mellon]

On 6/14/07, Peter Otten <__peter__ at web.de> wrote:
> Peter Otten wrote:
>
> > Leo Kislov wrote:
> >
> >> On Jun 13, 5:40 pm, ido... at gmail.com wrote:
> >>> Hi all,
> >>>
> >>> I am running Python 2.5 on Feisty Ubuntu. I came across some code that
> >>> is substantially slower when in a method than in a function.
> >>>
> >>> >>> cProfile.run("bar.readgenome(open('cb_foo'))")
> >>>
> >>>          20004 function calls in 10.214 CPU seconds
> >>
> >>> >>> cProfile.run("z=r.readgenome(open('cb_foo'))")
> >>>
> >>>          20004 function calls in 0.041 CPU seconds
> >>>
> >>
> >> I suspect open files are cached so the second reader
> >> picks up where the first one left: at the of the file.
> >> The second call doesn't do any text processing at all.
> >>
> >>   -- Leo
> >
> > Indeed, the effect of attribute access is much smaller than what the OP is
> > seeing:
>
> I have to take that back
>

Your tests (which I have snipped) show attribute access being about 3x
slower than local access, which is consistent with my own tests. The
OP is seeing a speed difference of 2 orders of magnitude. That's far
outside the range that attribute access should account for.