On Sun, Nov 05, 2006, "Martin v. L?wis" wrote:
> Greg Ewing schrieb:
>> Fredrik Lundh wrote:
>>>
>>> well, from a performance perspective, it would
be nice if Python looked
>>> for *fewer* things, not more things.
>>
>> Instead of searching for things by doing a stat
call for each
>> possible file name, would it perhaps be faster to
read the contents
>> of all the directories along sys.path into memory
and then go
>> searching through that?
>
> That should never be better: the system will cache the
directory
> blocks, also, and it will do a better job than Python
will.
Maybe so, but I recently dealt with a painful bottleneck in
Python code
caused by excessive stat() calls on a directory with
thousands of files,
while the os.listdir() function was bogging things down
hardly at all.
Granted, Python bytecode was almost certainly the cause of
much of the
overhead, but I still suspect that a simple listing will be
faster in C
code because of fewer system calls. It should be a matter
of profiling
before this suggestion is rejected rather than making
assertions about
what "should" be happening.
--
Aahz (aahz pythoncraft.com) <*> http://www.pythoncraft.co
m/
"In many ways, it's a dull language, borrowing solid
old concepts from
many other languages & styles: boring syntax,
unsurprising semantics,
few automatic coercions, etc etc. But that's one of the
things I like
about it." --Tim Peters on Python, 16 Sep 1993
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