[Python-Dev] [Python-checkins] r45925 - in python/trunk: Lib/tempfile.py Lib/test/test_os.py Misc/NEWS Modules/posixmodule.c (original) (raw)

M.-A. Lemburg mal at egenix.com
Tue May 16 13:40:01 CEST 2006

Martin v. Löwis wrote:

M.-A. Lemburg wrote:

Well, the strings and integers count twice: once in the module namespace and once in the errorcode dictionary. That shouldn't be the case: the strings are interned (as they are identifier-like), so you have the very same string object in both dictionaries. The numbers shouldn't be duplicated because they occur in the coconsts array of the global code object, and because the compiler should share them there.

Hmm, you're right.

Given that the code strings and integers are created twice in my version of the module, the numbers sound about right. If they are indeed created twice, something is wrong.

I agree that creating only one dictionary statically and the other mapping dynamically will already be a saving of 50% simply by sharing the string and integer objects. No, they should be shared already, so that shouldn't save anything.

I changed the generator to now use only one dictionary and create the module symbols at import time. Here's the new data:

USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND

Before:

lemburg 29980 0.0 0.4 19936 4620 pts/3 S+ 13:27 0:00 python

After the import:

lemburg 29980 0.0 0.5 20756 5260 pts/3 S+ 13:27 0:00 python

The RSS changed by 640kB - only 60kB less than with the static approach.

I also tried this on a 32-bit machine: the RSS changes by 392kB.

Next to come: the C extension version...

-- Marc-Andre Lemburg eGenix.com

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