[Python-Dev] genexps slow?
Michael Hudson
mwh at python.net
Wed Mar 31 05:45:25 EST 2004
"Tim Peters" <tim.one at comcast.net> writes:
> Resuming a generator function is a lot cheaper than calling a
> function, but there's still a non-trivial amount of code to get in
> and out of eval_frame() each time, which the listcomp version gets
> to skip.
This is something that occurred to me a while ago: how many opcodes
does a typical invocation of eval_frame actually execute? A little
script told me that the median length of functions in Lib/*.py was 38
instructions (or 52 bytes) IIRC, but obviously a dynamic count is far
more interesting. If the number is fairly small (and honestly, I have
no idea), the set up and tear down code becomes much more significant
than one might think.
I didn't think much about the code to get *out* of eval_frame.
Cheers,
mwh
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