[Distutils] Experience of setuptools' cache design

Viktor Fougstedt viktor at chalmers.se
Fri Jan 18 19:38:34 CET 2008

On 18 jan 2008, at 19.04, Phillip J. Eby wrote:

> At 12:50 PM 1/18/2008 -0500, Jim Fulton wrote:
>> Can you briefly explain or provide a link to something that explains
>> the performance improvement?
> Fewer directories on sys.path = better import performance, compared  
> to individually putting a series of .egg directories on sys.path.

Hi again, and thanks for the quick and interesting responses.

For me as a naive end user, the import performance is not critical on  
any system I run - my site-packages directories rarely contains more  
than five to ten packages, and have lots of CPU and I/O to use (I  
even believe frequently recurring stat():s are cached by the OS).

I am, personally, more concerned with a packaging system being  
scalable to many different computer systems, where user-id:s and home  
directories do not match (and many user-id:s, indeed, do not have  
home directories), where there are tens of thousands of users, or  
where there are two or three separate installations of libraries and  
binaries and the modules need to use the right ones depending on  
which python interpreter is run.

Being scalable to handle thousands of packages in site-packages is  
not on my personal list of priorities. It's all about which dimension  
you want the packaging system to be flexible in, I guess. My little  
vote goes to the "many users and strange systems" dimension. :-)

But who knows - many CPAN installations actually _have_ hundreds of  
dependencies installed. And with a packaging system that makes it as  
easy to install Python packages, perhaps the same will happen for us.


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